FAQ

The Cumulus FAQ (consult also the Help screens within Cumulus software, and the wiki)

Installing and Running Cumulus

What operating systems does Cumulus run on?

All versions of Windows from XP to Windows 8.1 inclusive (and the server versions). It works on 32 bit and 64 bit editions. It may also work on Windows 2000, but this is not supported. You will probably not be able to get it to work on Windows 2000 with a Fine Offset station.

Where do I find the Cumulus installer?

On the downloads page

What do I need to get right when first getting Cumulus?

The installation process for Cumulus displays readme.txt, that has many tips. See also Setup. Below are three key points.

1. Install Cumulus in its own directory directly under a drive root.
2. Connect your weather station before you start Cumulus
3. When you first run Cumulus, it displays the Station settings screen. On this, make sure you pick the right sort of station (to ensure Cumulus communicates correctly with your weather station, and can identify all the observations) and choose your units wisely. (Changing units later means all stored Lowest and highest numbers up to that point have to be converted immediately manually). See the Help for information about the rest of the screen, but generally you can easily adjust the other options later.

What weather stations does Cumulus work with?

• Davis Vantage Pro (VP), Vantage Pro2 (VP2), and Vue.
• Oregon Scientific WM918, WMR918, WMR928, WMR968, WMR88 (see this FAQ), WMR100, WMR180, WMR200.
• Fine Offset - stations which use the Easyweather software such as MyDEL, Nevada, Watson and Fine Offset, with model numbers such as WH1080, WH1081, W8681, 265NC etc.
• La Crosse WS2300 range (see this FAQ). You may have problems with corrupt data if you use a WS23xx with a serial/USB adapter; this combination is therefore not supported.

For a more complete list see the Supported Devices page.

Will you support a new weather station type?

It’s quite hard to support a particular weather station when I don’t have access to one. No weather station is perfect, and problems inevitably arise after the code is written, and I have to start adding more and more code to work around issues with the station. Also, most companies don’t seem to like third parties writing software for their stations, so don’t make the protocol available. I will only consider adding support for a station under a certain set of circumstances which would include at least:

• A significant donation towards Cumulus development
• A well documented official protocol spec
• Loan or donation of a station
• Access to technical support from the station manufacturer

Please contact me if you would like to discuss this further

How do I request a new feature for Cumulus?

Please create an enhancement request.

Why haven't you added the feature I asked for a long time ago?

I develop and support Cumulus in my spare time, and I have a full time job. I invite donations, but I don't make a living from Cumulus. I add facilities when I can. There is a long list of enhancement requests already, and I am slowly working my way through them as time permits. If there is an enhancement request for the facility you have asked for, and the facility is a reasonable one (in my opinion) then I will hopefully get around to adding it one day. Please be patient. Please don't ask for a forecast of when a feature will be added.

How do I upgrade to a new release?

Just run the installer for the new version. Your data and settings are not affected, but of course you should back up your data and any settings files (e.g. cumulus.ini and strings.ini) before you run the installer. You can install the new version where you like, but the installer will offer the same place as the previous version as the default. Occasionally, there may be actions you need to perform before or after the upgrade (these will be documented in the readme.txt file, this will appear as you run the installer). Required actions also usually appear in the announcement of the version you are installing.

During the install, you will be given the option of re-installing the Cumulus HTML template files. If you have customised the existing pages, you might want to untick this option so that your versions don't get overwritten. Alternatively store your customised pages in a directory outside the Cumulus folder, and specify up to 10 such files on the local side of the files tab in the Configuration menu Internet settings screen and untick Include Standard Files. (100 such files can be specified in Cumulus.ini).

Cumulus will always install the HTML template files to a folder called 'originals' in the 'web' folder, so you can look at them to see if there are any changes you might want to include in your customised versions.

These instructions apply whether you are upgrading to/from a beta version or a 'release' version.

Moving Cumulus software to a new PC (or updating Windows Operating System)

Cumulus will continue to work with your existing weather station and existing log files, providing

1. Your Windows regional settings are the same (i.e. date format unchanged, decimal point symbol unchanged, list sparator character unchanged) - if there is a difference, the new installation cannot understand the old lines in the file and will give an error when Cumulus is restarted.
2. You may need to 'tweak' a few things (serial port number etc) in cumulus.ini.
3. The Cumulus 'data' sub-folder has been copied across, together with 'cumulus.ini' from the folder with cumulus.exe in it, and if you have created a 'strings.ini' that file too.
4. Obviously if you use customised web pages, then you need the corresponding templates in the new installation.
5. Any other customised files (images and/or a twitter.txt file, for example), you may want to copy those over too.

Can I view my Cumulus data on another device?

1. If Cumulus uploads your weather information to an online web site, you can view that on another device.
2. Software like 'Remote Desktop' can be used to view the computer that is running Cumulus - see many postings on the Support Forum.
3. A back-up as described in the next answer can be viewed in Cumulus installed on another PC (see point about Windows regional settings in previous question) to look at past extremes or graphs; although obviously that additional installation will not be able to add further observations from the weather station connected to the original PC.
4. If your web site is on your local network, but not online, your device may be able to view it directly or view a back-up of how it was in the past.

How do I back up my data?

• Copy the contents of the Cumulus ‘data’ sub-folder on a regular basis to a different storage device. Then if you have any problem with the original storage device, or corruption of files, you can minimise the loss of logged observations. To restore from the backup, just copy the saved data folder back into your Cumulus installation, with Cumulus stopped.
• It can be useful to take copies of the Cumulus 'backup' sub-folder on key dates (e.g. just after change of month or year), or if you think you might have some rogue figures. The '.ini' files in the backup sub-folder contain past extreme values that you might want to look up.
• You should also back up, at least once, your cumulus.ini file in the main Cumulus folder. This contains all the key settings and you need a record of those!

Moving Cumulus software to a different location on your PC?

This article in the wiki gives more details above moving Cumulus: Moving cumulus

What are the formats of the Cumulus data files?

These are detailed in the Log Files section of this Wiki and also in the Cumulus help file, in the section “Data log file format”

Can I import logged information from before I installed Cumulus?

The Configuration menu, Station setting screen (near bottom) has option to enter there the rainfall total for the bit of the year (starting month can be selected here too) until when you first start using Cumulus. See the Cumulus Help for this screen for further details.

Yes is the answer for other weather information, providing you can manipulate the information you have into either (preferably) the format used by the Monthly_log_files#Importing_pre-Cumulus_data or (second best) Dayfile.txt. Look up those cross-references in this Wiki (or the Cumulus Help) for further information on required formats. The support forum includes a few threads related to this topic, and if you post there then people who have already imported from particular systems may offer their services to import your past observations.

A converter for Weather Display log files is available from this thread in the forum: http://sandaysoft.com/forum/viewtopic.php?f=4&t=10118

A converter for WeatherLink log files is available from this thread in the forum: http://sandaysoft.com/forum/viewtopic.php?f=6&t=11349

I was away on the last day of last month/year - How do I see the final lowest and highest figures for last month/year?

View, Highs and Lows - This month (or This year) (or thismonth.htm or thisyear.htm web page) only shows the lowest and highest values for the current calendar month (or current year). This answer describes a way to see the same information for the month (or year) that fairly recently ended. It is valid only until build 1088 (from 5 March 2014 build 1089 'Delay writing of end of day backup files until the first log entry is written' means the stored month.ini relates to the initial entries for the start of the new month). From version 1.9.3 build 1041, Cumulus creates a daily backup of the log files.

• Look in the backup\daily subfolder within your Cumulus installation.
• These daily backups will be created if Cumulus was left running during the period of interest, or stopped before that period and since restarted.
• Normally about 10 such back ups are available, each folder has a name based on the timestamp and contains the 6 xxxx.ini files, the current monthly standard data log/monthly extra data log, and the most recent update of daily summary log.

Open as a text file month.ini in the folder whose name is bearing the timestamp after your final rollover, for Cumulus builds 1041 to 1088 the final lowest and highest for each observation in the month will be listed.

In a similar manner if you miss the last day of the year, for Cumulus builds 1041 to 1088 see the final 'this year' figures for last year by opening year.ini from the appropriate backup.

What do the various wind speeds in Cumulus correspond to, with Davis stations?

Davis station firmware supplies two windspeeds, a 3-second average and a 10-minute average (later versions of the firmware also supply a 2-minute average, Cumulus currently doesn't use this).

• The latest Davis 3-second average is treated by Cumulus as 'Latest' (available via <#wlatest>)
• The highest of the station's 3-second readings over the previous 10 (configurable by adding AvgSpeedMinutes=N in Cumulus.ini#Section:_Station where 'N' is number of) minutes becomes the Cumulus 'Gust (available via <#wgust>)
• The Davis 10-minute average is the Cumulus 'Average' (available via <#wspeed>).

Note that if you sample these readings at shorter (real time) intervals it is possible for Cumulus 'Latest' to be lower than Cumulus 'Average' because approximately half of the 3-second wind speeds will be higher and half of them lower than the 10-minute average. If the Cumulus figure seems lower than the Davis figure see #My_Davis_station_shows_a_higher_maximum_wind_speed_than_Cumulus.

Davis station loggers record a single spot (not any average) wind speed, so if you restart Cumulus and the software attempts to catch up from the station logger there may be only one or two values to include in the Cumulus average (over 10 or whatever) minutes calculation.

What do the various wind speeds in Cumulus correspond to, with Fine Offset stations?

Fine Offset sensors measure wind over 48-second intervals, divided into 24 2-second intervals. At the end of each 48-second period, they transmit the highest of those 24 values as 'Gust', and the average of those 24 values as 'Wind'. The console keeps overwriting the newly received 'Gust' and 'Wind' values to the same area of console memory every 48 seconds, until the station logging interval time is reached, then it moves on to the next memory location, leaving the last values it wrote in the previous console memory location.

• If Cumulus is not running all the time, on restart it works through the console memory locations and extracts the Fine Offset Wind and Gust in each memory location, i.e. at the station logging interval.
• While Cumulus is running, it reads the current wind speeds (and direction) every 10 seconds. There are new values only every 48 seconds (i.e. every fourth or fifth read)

Cumulus, for various reasons, uses different terminology, and also has configuration settings which control how some of the wind values are displayed.

• The Fine Offset console 'Gust' value becomes Cumulus 'Latest'.
• The highest of the Fine Offset 'Gust' values over the previous 10 minutes becomes Cumulus 'Gust'.
• Cumulus 'Average' can be calculated in 3 different ways:
  • The default: If 'Calculate 10-min wind average' is not selected on the Station Settings screen, the console 'Wind' value is used.
  • If 'Calculate 10-min wind average' is selected, then by default the average of the Fine Offset 'Gust' values read over the previous N (configurable, defaults to 10) minutes is used.
  • If 'Calculate 10-min wind average' and 'Use speed for avg calculation' are both selected, the average of the Fine Offset 'Wind' values read over the previous N (configurable, defaults to 10) minutes is used.

Select value for 'N' using AvgSpeedMinutes=N in Cumulus.ini#Section:_Station.

Note that Fine Offset Consoles can display a 'MAX' figure, this is highest recorded since it was last reset (on touchscreen models multiple touches of the displayed speed will cause maximum speed, or gust, to be shown, and when a max value is displayed continuing to hold touching that value for 3 seconds will reset max to current value). Cumulus maintains its own various extremes for different periods (e.g High wind and high gust for yesterday on its main screen) calculated from all values read by Cumulus in that period.

How do I set up recording wind speeds in Cumulus, with Oregon Scientific and La Crosse stations

La Crosse and some Oregon Scientific weather stations only output a single wind speed. To allow Cumulus to calculate 'gust' and 'wind speed' with different values, select the Station dialogue from the Configuration menu and set Calculate 10 min wind average in the 'Settings' frame, so in cumulus.ini this will produce the parameter 'Wind10MinAverage=1 when cumulus is next stopped.

• The station's 'Wind' value will then display as Cumulus 'Latest'.
• A 10 (configurable by adding AvgSpeedMinutes=N in Cumulus.ini#Section:_Station where 'N' is number of) minutes average of the station's 'Wind' value will then display as Cumulus 'Average'.
• The highest of the station's 'Wind' value in a 10 minute period will then display as Cumulus 'Gust'.

See LCMaxWind=X parameter in Cumulus.ini#La_Crosse_specific: where X is the maximum (uncalibrated) wind speed in m/s that you want to allow.

How do I make Cumulus run automatically when Windows starts?

There is no option in Cumulus to set this up automatically as I prefer to leave it under the control of the user: The safest and most reliable method is simply to put a shortcut in your Startup folder. If you are running Vista or Windows 7, you may find that Cumulus gets blocked by UAC if you try to run it from the Startup folder, in which case it is recommended that you use Task Scheduler instead. See here for a good description of how to do this - http://blogs.techrepublic.com/window-on-windows/?p=616

How does Cumulus handle Daylight Saving Time?

As far as the timestamps in the extreme logs, monthly log, and the graphs, are concerned; Cumulus doesn't do anything in particular for DST. It generates timestamps based on the Windows clock. So basically, at the start of DST (i.e. when the clocks 'go forward') you will get an apparent gap of one hour in your data, and similarly at the end of DST (i.e. when the clocks 'go back') you will get an apparent hour of duplicate timestamps in your logs and graphs. You will tend to get better results if you leave Cumulus running during the clock change, because if it is stopped you may lose data, the exact timing of the affected hours depends on the type of station and when Cumulus was running.

Note that there seems to be an issue with Davis stations, either in the console/logger, or in the Davis DLL which Cumulus uses. If you don't have Cumulus running when DST ends, then when you start Cumulus up again, it doesn't receive all of the logger data it needs to catch up to the present time - the previous hour or so is missing. So with Davis stations, I strongly recommend that you leave Cumulus running at the end of DST, if at all possible.

For Fine Offset stations if you don't have Cumulus running when DST ends, then when you start Cumulus up again, the catch up misses off the first hour after the time Cumulus was stopped. This is because the console memory does not time-stamp the data blocks and Cumulus does not remember the console data block used just before shutdown, after all depending on how long Cumulus has been stopped and the station logging interval, the old memory location could be overwritten by now. On restart it just tries to read the appropriate number of hours worth of observations back from the block now marked as latest. If it was stopped at 2200 DST and restarted at 0600 standard time, Cumulus catches up with the last 8 hours worth of stored measurements as if going back to 2200 standard time, that means it stops at 2300 DST. At the start of DST, the catch up will duplicate the last hour that Cumulus was previously operating. (Stopping from 2200 standard time to 0600 DST the catch up goes back to 2200 DST or 2100 standard time).

What formula does Cumulus use for Apparent Temperature?

It uses a formula from the Australian BOM - http://www.bom.gov.au/info/thermal_stress/#atapproximation

Note that the version used is the one that doesn't take into account solar radiation.

How does Cumulus know the height of the cloud base?

It doesn't. It uses a calculation which gives the theoretical height above ground level at which Cumulus clouds might form, based on the current temperature and dew point. It assumes that the difference between temperature and dew point decreases by about 4.4 degrees Fahrenheit per 1000 feet increase in altitude. When the two values coincide, the air is saturated (relative humidity = 100%) and Cumulus clouds may form.

How is my rain rate calculated?

For stations which supply a rain rate, Cumulus uses that. For stations which don't supply a rain rate (e.g. Fine Offset and La Crosse), Cumulus simply takes the rain total from the last five minutes and calculates a rate based on that; e.g. a single tip of 0.3mm in 5 minutes is a rate of 3.6mm/hr. When data from the station's logger is used, a similar calculation is performed, but the interval used is the logger interval rather than five minutes.

Where does Cumulus get its this month and this year rainfall totals from?

• Each time Cumulus reads records from the weather station it applies any change to the 'total rain count' against today's total in its memory.
• The today's total so far at each reading time is also added to the 'recent tag' array allowing values for up to a week ago to be added as web tags to a web template.
• The rainfall totals that Cumulus uses when processing 'thismonthT.htm' and 'thisyearT.htm' web templates are initialised when Cumulus is (re-)started by adding up the corresponding daily totals in dayfile.txt and storing those sums in memory. To these are added today's total as currently in memory when a web page is created with those tags.
  • Important, for the <#ryear> web tag Cumulus reads the dayfile for the rainfall season starting with the month set on the station settings screen and stored as the value for attribute RainSeasonStart in Cumulus.ini#Section:_Station.
  • If you have set a 'year to date' value for the current year, that is also added into this year's total. There is no corresponding setting for 'this month'.
• Note that you need to stop and then restart Cumulus to update the initial values stored in memory and get any corrections to rogue values reflected on the main Cumulus screen and in web tags.
• The rainfall totals shown on the This period, This month, and This year screens within the View menu are generated by adding up the daily rainfall totals found in dayfile.txt for the selected period. So any rainfall for the current (meteorological) day is excluded as the latest dayfile.txt row is for yesterday. Totals are recalculated when you press the Update display button. Important note: The view menu 'This year' screen always calculates the total for a selected calendar year starting in January.

The built-in dayfile.txt editor is used if it is necessary to amend the daily totals (to correct any monthly, rain season, or calendar year, totals); the built-in all-time (or monthly records) editor(s) in Cumulus is used if it is necessary to regenerate the extreme records from dayfile.txt; see FAQ about correcting incorrect rainfall displays.

How do I reset all my data to start again from scratch?

Stop Cumulus and delete all of the files in the data folder. You may also want to edit the 'StartDate=' line in cumulus.ini to set the date for the start of your data.

How do I localise Cumulus to my own language?

Cumulus does not directly support languages other than English. It was never intended for use in other languages, and it is not possible to add support for this now. However, the text used for:

• Forecasting
• Moonphases
• Beaufort Scale
• Trend descriptions
• Compass points
• Graph titles
• Extra sensor channels

can all be customised by using the strings.ini file. This facility may be extended to allow other items to be translated, but it is very unlikely that there will ever be a fully multi-language version of Cumulus in its current form.

Also see this wiki page: Other Languages for information about customising the web pages.

Can I connect/disconnect my weather station while Cumulus is running?

No. You must make sure your weather station is connected to your PC and switched on, before running Cumulus. Do not disconnect your station while Cumulus is running.

How does Cumulus deal with extra sensors?

By default, Cumulus deals with weather stations incorporating solar sensors, if you have selected the relevant station 'Type' or 'Display solar/extra data' in configuration, but it has some capability to deal with extra sensors added including the Blake-Larsen Sun Recorder. Cumulus has the ability to input, log, and display Current Values/Outputs from the Hydreon Optical Rain Sensor - Model RG-11 and from either Oregon Scientific or Davis extra sensors. Only today's and yesterday's total rainfall from a Hydreon sensor are available in today.ini and yesterday.ini respectively. For some Oregon Scientific models, the temperature from an extra sensor can replace the temperature from the main sensor for processing by Cumulus, but all extra sensor values are stored in a series of monthly log files. No other processing is performed for Davis extra sensors, but past values are retained in a series of monthly log files. The file strings.ini is used to customise the description associated with extra sensors.

What is this "Solar Max" value which Cumulus is displaying?

It's the current theoretical maximum solar radiation value at the current date and time at your location. It is calculated using the Ryan-Stolzenbach formula, and uses the 'transmission factor' configurable in the station settings to allow for the effect of transmission through the atmosphere. The figure is not particularly useful in itself; it is used if you have a solar sensor, to compare with the current solar radiation reading, in an attempt to determine whether the sun is currently shining or not.

My Fine Offset console says the memory is nearly full - how do I clear it?

You don't need to, and it's much safer if you don't; clearing the memory could lead to a loss of data. The memory indicator on the console has no effect on the logging of data; the console will automatically start re-using the oldest memory locations. As long as you are running Cumulus (at least occasionally), Cumulus will have downloaded the data it needs from the console, so the console is free to overwrite the oldest data when it needs to.

How do I get my Davis station with USB working with Cumulus?

Cumulus cannot drive the station in USB mode, you must install 'virtual serial port' drivers, and configure Cumulus to use the virtual serial port. Make sure you have the station connected to the PC during the following operations.

You should first make sure that you can use the station with Weatherlink, in serial mode. If you have not already installed the Weatherlink software, install the version which came with your weather station. You should then upgrade to the latest version of Weatherlink; you can download the update from the Davis web site, here.

You now need to install the 'CP210X USB to Serial Converter'. You may find a link on your Start menu under 'Weatherlink'. Alternatively, you should find it in the folder where Weatherlink was installed, under 'Support' then 'Utilities'. Davis also make it available on their web site, here

It's a good idea to then update the driver to the latest version from the Silicon Labs web site, particularly if you use Windows 7 or 8. You can download it here - click on 'VCP driver kit' under 'Download for Windows XP/Server 2003/Vista/7' to begin the download. Run the executable once it's downloaded.

At this point, it's best to restart your computer.

You should now run Weatherlink, and attempt to connect to the weather station in serial mode. Weatherlink should find the appropriate COM port number automatically. If not, you can find it under 'Ports (COM & LPT)' in the Windows device manager. Look for the port called 'USB Serial Port (COMn)', where 'n' is a number. That's the number of the port you need to use in Weatherlink. If you cannot get Weatherlink to work using this virtual COM port, it is unlikely that you will be able to get Cumulus to work either, so either contact Davis support, explaining that you are trying to use the virtual serial port drivers because you want to run third-party software, or ask in the Cumulus forum, someone may be able to advise.

Once you have Weatherlink connected and working via the virtual serial port, close it down, and start Cumulus.

In the station settings in Cumulus, select the appropriate station type for your station; under 'VP Type' select Serial; in the serial port section enter the COM port number that you found earlier. You may need to restart Cumulus at this point. It will then start displaying live data. Note that the it deliberately does not download any historical logger data from before the current point in time. When you run it subsequently, it will download logger data to catch up if necessary from when you last ran it, but never from earlier than when you first ran it.

If you still having difficulty, the Davis Weatherlink manual offers this advice, which may be useful:

"Included with the WeatherLink software is a utility that allows you to convert a USB data logger from a direct USB data logger back to a USB data logger that emulates the serial port. To use this utility, select Convert USB to Virtual Serial in your WeatherLink program group on the Start menu of your computer (Start>AllPrograms>WeatherLink>Convert USB to Virtual Serial) and run the utility to convert your data logger. Please contact Davis Technical Support (“Contacting Davis Technical Support” on page 26) for more information."

Why does Cumulus do some things the way it does, when there are better ways?

Cumulus was originally something I 'knocked together' quickly when I got my first weather station, simply because I couldn't find any other software anywhere which I was prepared to use. No 'design' went into it, it was really just a prototype. Some of the things I did were just quick 'hacks' that I intended to fix when I did it 'properly'. But I never got around to going back and doing it 'properly', and it was never my intention that anyone else would use it. But I was persuaded to make it available for others, and then to add more and more enhancements.

The fact that it works with several different types of weather station means that much of it is a compromise; it doesn't use certain features of the weather station which it could use if it were dedicated to that type of weather station. For example, it typically does not use any high/low data that the station might store internally. Instead, it maintains its own high/low data from individual readings. There are a number of reasons for this; the fact that Cumulus supports an 0900-0900 day, and the weather station does not, and the fact that typically Cumulus maintains far more high/low values than the station does, and these need to be self-consistent.

So yes, I am aware that some of things that Cumulus does may seem strange, but it is simply not possible for me to start again from scratch, knowing what I know now. And it is not possible for me to effectively produce separate versions of Cumulus specifically for each type of weather station. If you don't like the way Cumulus does certain things, do what I did and write your own software!

Troubleshooting

My 'Error' light is flashing

Click on it, and a window will open describing the error. It may just be a temporary ftp problem. If you want to stop ftp errors being reported in this way, you can turn them off in the display settings ("Show FTP errors on error log window").

I’ve configured my ftp details but the web pages aren’t appearing on my site

Try setting ‘use active FTP mode’.

I’ve tried active FTP mode, but my web pages (or my realtime.txt file) still don’t appear?

Are you absolutely sure you have set the ftp path correctly? Most problems like this are a result of an incorrect path. Note that the information in the 'FTP progress' window is not generally useful for diagnosing upload issues' try turning on the ftp logging (on the Configuration menu) and look in the ftplog.txt and realtimeftplog.txt files (in the Cumulus folder). It is best to supply a relative path - i.e. with no leading 'slash'. Please don't ask me what path you need to supply, it is impossible for me to guess how your web space is set up. If you cannot work it out, ask your web space provider for help.

My ‘new record’ light has stopped flashing

It is the normal situation that the light does not flash. The ‘new record’ light only flashes when an all-time record has been broken. It stops flashing if you click on it or restart Cumulus, until another all-time record is broken. When you first start using Cumulus, inevitably the light will flash a lot, even if you cancel it, as you will be breaking records constantly. After a while, it will 'settle down' and not flash so often.

I installed a new version and my web page templates got over-written

The supplied web page templates are part of Cumulus and will be over-written on upgrade. If you want to create your own web pages, don’t edit the supplied ones, place them in a different folder and use the ‘extra files’ facility. From version 1.8.9, the installer offers the option of not over-writing the web templates; it unconditionally also installs them to a sub-folder of the web folder called 'originals', so you can refer to them if required, even if you chose not to over-write those in the web folder.

I can’t find my data files!

You’re probably running Windows Vista/Windows 7/Windows 8 (or one of the corresponding server versions of Windows). Look in C:\Users\[username]\AppData\Local\VirtualStore\Program Files\Cumulus - note that this is a 'hidden' folder. Ideally, to avoid this situation, you would install to somewhere outside the Program Files hierarchy, as recommended in the readme.txt.

I can't save my NOAA reports!

You've probably corrupted your Cumulus.ini file in the default Cumulus folder. See Cumulus.ini#Section:_NOAA. It can only be edited either (if Cumulus is stopped) with an external text file editor or (with Cumulus running) using the NOAA Setup in the configuation menu. Pay attention to where the quotes are required for the file names, and check that you have an allowed date format (see Webtags#Time.2FDate_.27format.27_Parameter).

My sunrise and sunset times are wrong

You've almost certainly entered your co-ordinates incorrectly, or not entered them at all - on the station settings screen. You must enter DEGREES, MINUTES, and SECONDS, no other format will work. Make sure to use unsigned whole numbers for degrees, minutes, and seconds, with a 'W' for your longitude if you're West of the Greenwich meridian (e.g. if you are in the United States), and the appropriate letter for your latitude (N for northern hemisphere, S for southern hemisphere).

If you are not familiar with the degrees/minutes/seconds standard format and have your co-ordinates in some other format, there are pages on the web which will convert for you. One such is here: http://transition.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html

One other less likely possibility is that you have set the wrong time zone on your PC.

The Moon rise or set time is showing dashes.

The moon doesn’t rise and set every day, the dashes appear when that event doesn’t occur on that particular day. The period between a moon rise and set is approximately 12 hours and 25 minutes, on average. The moon rises (or sets) approximately 50 minutes later, on average, each day. It therefore follows that sometimes the moon will not rise or set on a particular day - i.e. it had risen the previous day, or will set on the following day.

The Moon image is just black

It's probably a New Moon.

Why are the 'Yesterday' figures missing on the Main Cumulus Screen?

The yesterday values on the Main Screen under "Recent Extremes" are not shown correctly:

• EITHER when the end of day rollover has not taken place. The usual cause of this is allowing your PC to 'sleep' while Cumulus is running. The support forum mentions a few other causes.
• OR if Cumulus was unable to read observations from your station during that day, but can today.

I’ve ‘zoomed’ a graph, how do I get it back to full size?

Drag from lower right to upper left.

My station invented some rain that didn't really occur, and I want to set it to zero (or some other figure)

(Invented rain) Error in today's total

1. correct today's total using the 'today's rain' editor on the edit menu.
2. optionally stop Cumulus and edit today.ini to change the LastTip=(look up previous value in a recently backed up today.ini) parameter.
3. Remember that 'ConsecutiveDryDays' and 'ConsecutiveWetDays' do not include today.

(Invented rain) Error in yesterday's total

1. edit the total for the relevant day in dayfile.txt, using the dayfile.txt editor on the edit menu.
2. optionally edit yesterday's total (which is only held temporarily for display purposes) in today.ini, while Cumulus is stopped.

(Invented rain) Error in total or high rainfall rate for any day before today

Just edit the total or rate for the relevant day in dayfile.txt, using the dayfile.txt editor on the edit menu.

(Invented rain) Error in total, or extremes, for this month and/or this year

See next FAQ. Once you have corrected the daily totals (or high rainfall rates) in dayfile.txt, you can use the editors (on the edit menu) for 'This Month' and 'This Year' to fetch the corrected values from dayfile.txt (or enter figures manually).

(Invented rain) Error in all-time records

If your all-time records, or month-by-month all-time records have been affected, you can use the built-in editors to fetch the correct values once you have corrected dayfile.txt.

(Invented rain and) Other rain figures

Note that other rain figures, such as 'rain last hour' and 'rain last 24 hours' depend on a sensible progression of the rain counter, so it's not easy to correct this; it's easier to wait until the erroneous figure is far enough in the past so as not to affect the calculation. If you really do want to try to correct it; you would need to stop Cumulus, then find and edit multiple field 11 (assuming date is field 0) the 'total rain counter' values in the monthly_log_files in the current monthly log file so they are correct relative to the current value of the rain counter (i.e. the latest one logged).

(Invented rain) Error prevention by Spike removal

1. It is better to try to avoid spurious rain being recorded in the first place.
2. Cumulus attempts to ignore large increases in the rain total automatically, and is quite often successful.
3. For 'hourly rain' and 'rain rate', you can set 'spike removal' settings on the calibration settings screen. The value you set here, is the maximum change allowed between successive observations. These apply only to Fine Offset and La Crosse stations (which are known to occasionally produce faulty rain readings).

(Invented rain) More information

There is more information about correcting rogue data elsewhere in the Wiki, in the pages about the log files.

My monthly and/or annual rainfall totals are wrong

Cumulus calculates these when it is restarted, holds the values within memory, and increments them as required while it is running. This FAQ in the previous section #Where_does_Cumulus_get_its_this_month_and_this_year_rainfall_totals_from.3F has a concise description of how Cumulus calculates these figures.

• The rainfall total shown on the This month screen within the View menu, is calculated from summing dayfile.txt totals for a selected month, and so for the default current month will exclude the current meteorological day. The rainfall total for today so far is added for the web tag <#rmonth>.

• The rainfall total shown on the This year screen within the View menu, is calculated from summing totals in dayfile.txt for a selected calendar year. For the default current year, it will exclude the current meteorological day.

• The rainfall total reported by the <#ryear> web tag is for the rainfall season to date, it is calculated from taking today's rain and then adding the sum of the totals in dayfile.txt starting with the first (meteorological) day of the month specified in the 'rainfall season' frame on the station settings screen within the Configuration menu, until the end of dayfile.txt is reached. So check you have specified the right starting month there before deciding the rainfall total shown is wrong.

If you need to, you can specify a year-to-date total to add in for the period up to the point where you started using Cumulus, so that your first year’s total is correct. This is also on the Station Configuration screen. Make sure you specify the first Cumulus operating year here, otherwise the extra will be added to the annual total for the wrong year!

See immediately preceding FAQ correcting rainfall for how to correct errors in total for particular days and how to correct the high extremes for the various periods.

In all cases then restart Cumulus to get the monthly and annual totals recalculated from correct daily totals.

If you need to correct within day values for trend graphs as well as the longer period totals, provided you know roughly when the rogue rainfall was recorded, find (and edit) it in the monthly_log_files, field 11 (assuming date is field 0) is the count used to derive other parameters.

The ‘gust’ line has disappeared from my graph

You probably have Cumulus set to calculate a 10-minute average, and your logger period is 10 minutes or longer, so your gust comes out the same as the average when using data from the logger.

My ‘gust’ values are the same as my ‘average’ wind speed values.

As above, you probably have Cumulus set to calculate a 10-minute average, and your station logger period is 10 minutes or longer, so your gust comes out the same as the average when using data from the logger.

I’ve just installed Cumulus, and it didn’t download all the old data from my weather station

Cumulus deliberately doesn’t attempt to download any data from before the point when you first run it. If you wish, although this isn't recommended, you can force it to download data from any point by editing the ‘Timestamp’ line in the today.ini file (in the data folder), before starting it (you will need to have run it at least once previously). Note that if you do this, it is at your own risk, and you will need to sort out any issues which may arise yourself.

If you do this, you will probably need to edit your log files in the data folder as you may have duplicate entries and/or entries out of order. Your rain totals will almost certainly also be wrong - the total for "today" in particular. See the FAQ entry about correcting rainfall data. If you have only just started using Cumulus, you could delete all of the files in the data folder, and just create a simple today.ini as below. Then when you start Cumulus it will start again with just the data from the station's logger.

Note that this method does not work for the Oregon WMR200 station. This station deletes logger entries when they are downloaded, and there is no mechanism for retrieving logger entries for a particular period - it just sends all the entries that it has. You may be able to circumvent this by creating a today.ini file in the data folder before you run Cumulus, with just this in it:

[General]
Date=10/04/2012
Timestamp=10/04/2012 10:00:00
CurrentYear=2012
CurrentMonth=4
CurrentDay=10

Change the dates and time to match the point from which you want Cumulus to start downloading data. If the station has already sent the data, this may not work, unfortunately.

If you stored data from your weather station (on another file-based system) before you first ran Cumulus, then you may be able to (using a text editor outside Cumulus) generate Monthly log files for the pre-Cumulus period. See that Wiki article for more information on what you can then do with those files within Cumulus.

I have inserted pre-Cumulus data and now I get errors

Probably some of your inserts used the wrong format (blank rows, fields with real numbers where integers expected, alternatively missing or duplicated fields). See Category:Log_Files. Note that Cumulus will only flag errors in the log files that it reads (e.g. those relating to the period for which it displays trends graphs). Check all the log files you have amended.

I have inserted pre-Cumulus data making 'Records began on' date wrong

Stop Cumulus and edit cumulus.ini (station section) within the main Cumulus folder. Change the "StartDate=" line. Be sure to use the same format for the date.

Note StartDate=xxxx does not need to be updated for Cumulus to recognise earlier data in log files in its data subfolder.

It really represents "Cumulus began on", so there is an alternative of leaving cumulus.ini unchanged, but editing default Cumulus recordsT.htm template twice:

• after the h2 heading is <p>Records began on <#recordsbegandate>. Here are the extremes recorded since then.</p>; you can replace '<#recordsbegandate>' with the new earliest date typed in as text; and
• at the start of the table is the <caption>Records Since <#recordsbegandate></caption>; replace the label "Records since" with "Cumulus began on" leaving the web tag unchanged.

Cumulus doesn’t show the same pressure as my Fine Offset console

Cumulus displays atmospheric pressure corrected to sea level. The console calls this ‘relative pressure’; it displays the letters "rel" when this is being displayed. First of all, check

1. that you are comparing the Cumulus display with the ‘relative’ pressure on your console,
2. that only one copy of Cumulus is accessing the weather station (and no other software),
3. that you do not have a 'EWpressureoffset=x.y' line in the [Station] section of cumulus.ini,
4. and that you do not have a setting for pressure on the Cumulus calibration screen.

The Fine Offset stations only store absolute/station pressure readings in their weather memory locations updated with each transmission and read by Cumulus. Within Cumulus, the software applies the adjustment to sea level before any further processing. It does not use the altitude setting in the cumulus station configuration screen. Normally when Cumulus starts, it reads in the fixed block in the console a pair of absolute/station pressure and relative/sea level pressure readings and uses the difference between these as the ‘offset’ in millibar for the station; Cumulus uses this offset subsequently to calculate the sea level pressure (each time when reading the absolute pressure in the weather memory locations of the station), but it is possible to define the offset in cumulus.ini instead.

Make sure that you have set your console's relative pressure correctly:

• for a push button operated model, press 'menu' key 4 times for pressure mode, press 'enter' to move to relative pressure setting, press 'up' or 'down' to adjust value.
• if your model uses a touch sensitive screen then it is probably tap the reading three times, then touch '+' or '-' to adjust value.

The support forum includes discussion on where to find isobar charts or other sources to determine what the pressure should be. Obviously after any adjustment you need to stop Cumulus, because it is when you restart it that Cumulus reads the new pressure offset.

Sometimes the offset that cumulus reads from the fixed block is clearly garbage, so

1. the cumulus error light is set,
2. an error message suggests you check the station, and
3. Cumulus uses zero offset instead as a best effort.

In this situation, Cumulus will display the same value as the 'absolute' pressure on the console (no "rel" is displayed on the console when it is displaying absolute pressure). Often, if you restart Cumulus, it will then be able to read the correct value. If the problem happens often, you can circumvent it by editing cumulus.ini (while Cumulus is stopped), and in the [Station] section add an entry:

EWpressureoffset=x.y

where x.y is your pressure offset. Cumulus will then use this instead of reading the fixed block offset from the station. Note that you must supply the offset in hPa (i.e. the millibar units that the station works with) and that this circumvention generally stops Cumulus from agreeing with the relative pressure displayed on the console.

My pressure suddenly dropped! Or suddenly increased!

If you have a Fine Offset station, and this happened when you (re)started Cumulus, it is quite likely a problem with reading the pressure 'offset' from the station. See: "Cumulus doesn’t show the same pressure as my Fine Offset console" above.

I get an error when I try to view my all-time records. Also, they don’t appear on my web site

The date format on your system has probably changed. Look at the Startdate line in cumulus.ini and check whether this is in the correct format for your system. If not, stop Cumulus and correct the date format.

I get an error when I close Cumulus

Cumulus does sometimes report an error when you close it. This does not appear to cause any problems, you can just close the error message. I don't seem to be able to do anything about this, as the 'crash' is not in code that I have control over. You may be able to avoid this error by avoiding closing Cumulus while it is uploading to the internet. Please don't bother sending me a bug report about this.

My forecast says "Not available"

You can get Cumulus to create a simple forecast by selecting 'Cumulus Forecast' on the Stations Settings screen.

My forecast always says "Exceptional Weather, Stormy, much precipitation"

You probably have incorrect Pressure Extreme settings in the Forecast section on the Station Settings window. Make sure that the values you have supplied match the units you have selected for the extremes. Note that the units for the extremes are not related to the units you have chosen for pressure display in Cumulus. The option of supplying mb/hPa or inHg for the extremes is merely a convenience; you can supply either, but the values and the units must of course match.

My computer hibernated/suspended, and I lost data/my graphs 'flat-lined'

Cumulus can't cope with being suspended, it just carries on as normal after being woken. There is an option in the station settings to 'close on suspend', so Cumulus will close itself as a safety measure, if you forget to do it manually. Don't use the 'close on suspend' option and the 'confirm shutdown' option at the same time; this will cause problems.

But I strongly recommend that you don't have your computer set to go into any form of standby while Cumulus is running - it's continuously gathering real-time data, after all, so it's a rather strange thing to do.

My heat index/humidex/wind chill is the same as my temperature

• Wind chill only applies when the average wind speed is above 4.8 kph and (by default in Cumulus as it should really always be set, but this is an option that can be unset) the temperature is below 10 degrees Celsius.
• Heat index only applies when the temperature is above 27 degrees Celsius and the humidity is above 40%.
• Humidex does not have any 'cutoff' values, but at low temperature and/or humidity it will give the same figure as ambient temperature.

If heat index or wind chill is not applicable, Cumulus will set them the same as the ambient temperature.

Cumulus is showing a different wind speed compared to my console

You have probably misunderstood Cumulus processing of wind speeds, looking at different parameters, or different averaging periods.

• If you have a Davis weather station see #What_do_the_various_wind_speeds_in_Cumulus_correspond_to.2C_with_Davis_stations.3F
• If you have a Fine Offset station, see #What_do_the_various_wind_speeds_in_Cumulus_correspond_to.2C_with_Fine_Offset_stations.3F
• For Oregon Scientific and La Crosse stations see #How_do_I_set_up_recording_wind_speeds_in_Cumulus.2C_with_Oregon_Scientific_and_La_Crosse_stations

Note that you can't compare the graphs drawn by Easyweather and Cumulus unless you are certain that they are plotting the same data. They can't both be running at the same time, so one would normally be plotting 'live' data at a given interval, and the other will be plotting data downloaded from the station's logger. The wind speed will hence not normally be the same for a particular time on the graph as it may well have changed at the point that it is saved to the logger. The only situation where it would be valid to compare the graphs would be if neither were running at the times you are comparing, and both subsequently downloaded the same data from the logger.

I get error -32710 with Cumulus and my USB Davis station

The USB support in the Davis DLL which Cumulus uses doesn't seem to work. You need to use the CP210X USB/serial software which Davis supply, and use the station in serial mode. If you have previously been using your station with Weatherlink in USB mode, you will need to change to serial mode in Weatherlink before you can use the station with Cumulus. You can do this using this utility from Davis.

When I start Cumulus, the graphs restart again each time and don't show the earlier data

You probably have an error in one or more data files. Look near the beginning of the latest file in the Diags folder for an error message which will tell you which file is in error and which line is causing the problem. It may simply be a blank line. Edit the file with Cumulus stopped. Note that you may need to repeat this process; only the first error is shown.

This problem can also occur if you change your system format settings (date format, decimal and list separators etc). Again, check the diags file for a message about a number not being a valid floating point value.

Cumulus won't read the data from my station

If you have one of the Fine Offset clones, make sure you have configured your relative pressure correctly. If Cumulus finds an 'impossible' value, it will ignore all data from your station.

The peak values on my graphs are not the same as my extreme values

The graphs are snapshots of the data, taken once a minute while Cumulus is running; it is not feasible to plot every data point. If the extreme value did not coincide exactly with the point at which the data was added to the graph, then it will not appear on the graph. The graphs are not intended to show all of the highs and lows, they are there to give an idea of the trends. This also applies to 'Select-A-Graph', which takes its data from the data logs; the highs and lows do not necessarily appear in the periodic data logs.

This is most noticeable with wind gusts, the value of which can change rapidly, even over a period of a minute. The 'Plot latest gust' setting causes the 'Latest' figure (as shown on the main screen) to be plotted. What this figure represents exactly depends on your weather station type. This figure may vary rapidly, e.g. on Davis stations, it changes every 3 seconds or so. The graphs are plotted once a minute, and hence, with Davis stations, for example, there is approximately a one in 20 chance of any given 'latest' figure actually being plotted.

Cumulus also stores the peak value of the 'latest' figure from the last 10 minutes. It calls this the 'gust', as this is a reasonable representation of a true 'gust' figure. If you untick 'plot latest gust', it will plot this figure instead. As it contains the peak figure from the last 10 minutes, and the graph is plotted once a minute, plotting this value means that the high gust figure will always appear on the graph. The exception to this is with Davis stations, in the situation where the 'high gust' figure has been read directly (as a way of ensuring that the high gust isn't missed) rather than by the usual reading of the current data. In this case, the gust is recorded as the high, but is not written to the current value, and hence does not appear on the graph, as it may be out of sequence with the current data.

My extreme values do not appear in the 'monthly' data logs

The data logs are snapshots of the data, taken at the configured interval while Cumulus is running (or at the station's configured interval when data is read from the station's logger directly into the Cumulus monthly log). Cumulus, while it is running, reads the station frequently, detecting each change in observations, and can update extremes at each of these reading times.

If the extreme value reading time did not immediately precede a time at which the data was logged, then it will not appear in the log. This is most noticeable with wind gusts, the value of which can change rapidly between log entries.

Cumulus is designed to be kept running, if you only run it once a day, then the information it reads from the station's logger during catch up may miss extremes. For example when Cumulus reads the archive temperatures from a Davis station, (in a compromise to allow Cumulus to have as much code as possible that is common to all weather station types) the design means that it ignores the first and second figures representing highest and lowest reported at each logged time, just reading the third figure that, depending on console configuration, is either the average value over the archive period or the final reading of the archive period (I don't know what the default is).

Cumulus takes a long time to download the data from my Davis station at start up

When Cumulus starts, it asks the station for all the data from the logger since the last time it was running. If the timestamp that it supplies does not exactly match the timestamp of an entry in the Davis logger, the station has a strange 'feature' where it decides to send the entire contents of the logger. This will take some time to download, during which the Davis console display may appear to freeze.

It is recommended that you set the logging interval in Cumulus to the same interval as the station (the station interval can be changed using Weatherlink), then Cumulus will be able to make sure it uses a timestamp that matches an entry in the logger. Note that this is mentioned in the readme.txt file which appears during the Cumulus installation, which you were asked to read at the time. If you didn't read it, it is strongly recommended that you do so now; it contains important information.

Today is the shortest/longest day, but Cumulus says that tomorrow will be a few seconds shorter/longer

The routines I use to calculate the length of the day aren't really suitable for this level of accuracy. I don't consider it an issue.

Cumulus got the forecast wrong!

Cumulus uses a forecast based on the Zambretti Forecaster (see Google). I didn't design the algorithm myself and to be honest I don't know how it works, so I can't answer any questions about it. Note that this is a 'forecast' for the following 12 hours or so; it is not a 'nowcast' (what the weather is doing now). Please regard the forecast as 'for entertainment purposes only'. Do not base any decisions on it, and bear in mind that it is a very simple calculation based on only a few basic parameters. Some people get reasonable results, others do not. You can try tweaking the pressure extreme settings (in the Forecast section in the station settings), but don't expect the forecast to be as good as that provided by the weather agencies which have invested millions in their forecasting systems.

I only see one set of points on the wind direction graph

This happens just after you restart Cumulus, if the data came from the weather station's logger (i.e. Cumulus hasn't been running for a while). Weather stations only supply a 'current' direction, and Cumulus calculates the average direction when running 'live'. So there is only one set of data available to be plotted, if it comes from the station logger.

My average wind bearing remains at zero

Cumulus will always show zero average bearing when the average wind speed is zero (it can't be otherwise because it's calculated using the wind speed). In addition, it will show zero current bearing when the current wind speed is zero if you have use bearing zero when calm selected in the station settings (accessible from Configuration menu).

This also happens if your anemonmeter has a fault.

My graphs appear to be plotted less frequently just after Cumulus starts up

When running live, Cumulus plots data at 1-minute intervals. When it starts up, it pre-fills the graphs with data from the log files, which generally (depending on how you have Cumulus and your station configured) will be at less frequent intervals.

I closed Cumulus, the 'please wait' form appeared, but Cumulus didn't close, even after several minutes

If you've closed Cumulus shortly after it has downloaded a lot of data from the logger, it can take a while for the logging thread to get everything written away to disk, and Cumulus won't close until this has completed. However, in some circumstances, there seems to be a situation where Cumulus will never close, so you will need to close it with task manager. If you think you know what conditions cause this to happen, please let me know.

Cumulus isn't logging data at the interval that I set

It logs data at the interval you have configured, while it is running. If there is data to read from the station logger at start up, each logger entry is logged to the Cumulus log files, so those entries will be at the logger interval that you have configured in your station.

Cumulus takes a very long time to shut down

You may have closed it very soon after starting it up, when it had a lot of data to download from the station logger, and you use Weather Underground. From version 1.9.1 there is a facility where it 'catches up' with data that hasn't been uploaded to Weather Underground while it hasn't been running. This takes a little while, and if you close it while it is doing it, it will take a long time for all of the updates to time out. You need to give it sufficient time to finish the upload. From version 1.9.2, there is a 'catch up' light which shows that the upload is taking place, and the 'catch up' is optional'; and it will abort much more quickly if you still close it while the catch up is taking place.

My temperature Min/Max/Avg graph is empty

The most likely explanation is that you have only recently started running Cumulus (in the last day or two). It adds new values to this graph at the end of each day; it wouldn't make sense to add a value part of the way through the day, and you need a few points to be plotted before the graph starts to take shape. You need to wait until you have been running Cumulus for a few days.

If you've been running Cumulus for more than a few days, but the graph is still empty, the most likely explanation is that it was unable to read your dayfile.txt file. Look at the latest file in the 'diags' folder (the files are plain text) for error messages mentioning dayfile.txt.

The longest dry/wet spell for this month/year includes days from last month/year

This is intentional. I decided that it didn't make sense to arbitrarily chop off a dry/wet spell at the start of the month/year, as then the figure is meaningless. So the figures are to be interpreted as "the longest dry/wet spell which includes this month/year". I note that other software takes the same approach.

Cumulus isn't performing periodic tasks, like data logging or web uploads

Cumulus assumes a certain level of weather station functionality. It checks that it has received data from a number of sensors (e.g. pressure and outside temperature) before it starts logging or uploading to the web, or drawing graphs. If your weather station is not fully functional, you will not be able to use Cumulus fully.

• From version 1.9.3 onwards, you can over-ride the start up check by adding a line to the Cumulus.ini#Section:_Station, thus: NoSensorCheck=1
• From version 1.9.4 onwards: Option to turn off reporting of 'lost sensor contact' for Fine Offset stations. Add a line to the [Station] section of cumulus.ini, thus: ReportLostSensorContact=0

I've changed my Twitter password, and now Cumulus won't update Twitter

You need to force Cumulus to re-authenticate with Twitter. Stop Cumulus and edit cumulus.ini. Find the [Twitter] section, and delete the lines which start

OauthToken=

OauthTokenSecret=

Start Cumulus and it should be able to update Twitter again.

When I start Cumulus, I get the error message "The station is not initialised"

For Fine Offset stations, when Cumulus starts up, it checks the first two bytes of the station's memory. They are supposed to contain the values Hex 55 and Hex AA to indicate that the station has initialised itself correctly. If they do not, then presumably the station has had some kind of internal problem, so Cumulus doesn't try to read any data from it. A reset of the station normally fixes this - remove the batteries and the USB cable; but note that you will almost certainly lose any stored data in the logger.

If you want to force Cumulus to ignore this check (not recommended), edit cumulus.ini and add a line to the [Station] section: EWdisablecheckinit=1

You will most likely not have any success with this, as your station memory is probably corrupted anyway.

Note that for this setting to work, you need to be using version 1.9.3, build 1034 or later.

How do I correct today's or yesterday's highs and lows?

Today's totals, highs and lows (and yesterday's rain total) are held in today.ini in the Cumulus data folder. Yesterday's totals (including RG11 rain but not standard rain), highs and lows are held in yesterday.ini. Follow the cross-references if you are unsure which parameter is what. To change any values, stop Cumulus and edit the file(s) in a text editor. Be sure to keep any date and time formats the same. If you are editing yesterday's highs and lows, you might also need to edit dayfile.txt, as the same values will probably have been written to that file. You can use the built-in dayfile editor in Cumulus to do this. If your all-time and/or monthly all-time records have been affected, see the FAQ entry below.

If the value you want to change is today's high hourly rain figure, it is best to wait until the current figure has returned to a sensible value. There is no easy way to correct the current figure, so if you change it in today.ini while the current figure is incorrect, the high value in today.ini will immediately be changed again when you start Cumulus. More information about correcting rain in this FAQ.

If the problem occurred because Cumulus wasn't able to download the data from the station's logger when you started it up in the morning (or perhaps you turned off the 'use data logger' setting for some reason), you can get it to try again by 'rewinding' to the time when you started Cumulus, and allowing it to try again. Cumulus takes a copy of the current files each time it starts up, and puts them in a folder in the backup folder in the Cumulus installation. Stop Cumulus, and find the backup folder with the appropriate timestamp, and copy all of the files from the backup folder into the Cumulus data folder, and start Cumulus up again.

How do I correct my all-time (or monthly all-time) records?

Use the editor in Cumulus - on the Edit menu. If you know the correct figures, you can enter them manually.

• You can look at the Alltimelog.txt file to find the previous values for the all-time records.
• Similar entries are logged to the diags files for the monthly highs and lows in month.ini.
• You can also get the editor to scan the daily summary log and Monthly_log_files to find the highs and lows from those files, click the Help button for details. Note that to use this facility you first need to correct any incorrect values in the files being scanned; you can use the built-in editor in Cumulus to edit dayfile.txt.

Cumulus takes a backup of all the active data files when it starts up, and also at the start of the meteorological day (just after midnight for a lot of users). The backups are kept in folders within the backup sub-folder in the Cumulus installation. So an alternative method would be to find the latest backup from before the error occurred, and copy the alltime.txt and/or monthlyalltime.txt file from the backup to the Cumulus data folder. Do this with Cumulus stopped.

There is more information in Category:Log_Files, on the page for each type of file.

It's January 1st and my 'rain since midnight' and/or 'last 24 hours rain' are wrong/negative

You are probably using a Davis station. Cumulus needs an incrementing rain counter to calculate all of the rain figures, and the nearest to that on a Davis station is the annual total. When this resets at the end of the year, this causes some of the rain data to show odd values for a day. You will notice this particularly if you use an 0900 start of meteorological day, as the 'rain since midnight' figure is used for services such as Weather Underground. There's no easy solution to this, sorry.

Cumulus stops at the "Downloading data" screen

If you have a Fine Offset station, this is probably caused by the station's interface locking up. You should be able to get it going again by doing a reset - remove batteries and the USB cable. Recent Fine Offset models have a problem where they can lock up frequently, requiring a reset. From version 1.9.3 of Cumulus onwards, there is an option to synchronise the reading of data with the console writing the data, to avoid doing both at the same time, and this seems to avoid most lockups. The setting is "Synchronise Fine Offset reads" on the station settings screen.

If you look in the status bar at the bottom of the Cumulus window, there may a message "Error: no response"; this would confirm that the station has locked up and needs resetting.

Cumulus locks up when it starts and I have to use the task manager to kill it

If you have a Fine Offset station, this is most likely caused by the station's interface locking up, i.e the station has stopped communicating with the PC.

The problem where Cumulus locks up when the Fine Offset station doesn't respond is fixed in version 1.9.4. If you look in the status bar at the bottom of the Cumulus main window, there may be a message "Error: no response"; this would confirm that the station has locked up and needs resetting.

You should be able to get the station going again by doing a reset - either remove console batteries and the USB cable or press the reset button hidden below the small hole (on 1081-based models, above the top RH corner of the battery cover). Recently manufactured Fine Offset models have a problem where they can lock up frequently, requiring a power reset. From version 1.9.3 of Cumulus onwards, there is an option on station settings screen to Synchronise Fine Offset Reads (Cumulus reading data from console) with the timing of received transmissions from sensors updating the data, to avoid doing both at the same time, and this seems to avoid most lockups.

Error messages with "Error on line..." or "Error at line..."

These are corruptions in the log files, typically caused by Cumulus being unexpectedly closed (e.g. killed using Task Manager, or a PC reboot) while it is writing to the log files, but there can be other causes. The error message may say something like "List index out of bounds". The error message will name the affected file(s) and the affected line number(s). Stop Cumulus and open the named file(s) in a good text editor such as notepad++. Go to the line number(s) mentioned and correct the error(s), which will be obvious as the lines won't look like the other lines, they will be blank or have garbage characters, or perhaps two lines have been run together. Save the file(s) and start Cumulus again.

Cumulus gives an error and won't run on my HP computer

It's a known problem with HP computers; they have missing fonts. One solution is to install this font update from Microsoft. It appears that computers other than HP can have the same font issue, so it is worth installing the font update anyway, if you get a problem where Cumulus won't start.

The headings or data look wrong in the data log viewer

You're probably trying to view the wrong type of file. "View | Data logs" is only for the monthly data logs, e.g. Oct13log.txt, "View | Extra data logs" is for "extra" data logs, e.g. ExtraLog201310.txt, and if you want to view the daily summaries in dayfile.txt, use the dayfile.txt editor - "Edit | dayfile.txt".

The wind rose in Cumulus does not display anything with my Fine Offset

The Fine Offset weather stations are supposed to supply data for 16 wind directions, however the design is such that most of them only actually use 8 of the possible 16. Try setting the wind rose to only display 8 directions by setting the 'wind rose points' value to 8 on the display settings screen.

My Davis console clock is not exactly the same as my PC clock, but I have "Synchronise station clock" selected

The Davis protocol only allows hours and minutes to be set, so there is always likely to be a difference of up to a minute between the PC and the station.

I've set the graph background to white, but there's a problem with the small wind direction graph

This appears to be an issue with the third party chart component. The work around is to choose a gradient background and set all three colours in the gradient to white.

My Weather Underground tabular data interval is not the same as the interval I've set in Cumulus (I'm using Rapid Fire)

If you have selected 'rapid fire', the data is uploaded every 5 seconds, and the interval you configure in Cumulus is not used. Weather Underground decide how often your tabular data is logged when using rapid fire, not Cumulus.

My monthly (month-by-month) all-time records don't have entries for all of the months that I have been using Cumulus

You need to initialise them. See the release announcement for version 1.9.3, which is when this facility was introduced: http://sandaysoft.com/forum/viewtopic.php?f=2&t=9286

You only need to do this once; when you have initialised them, Cumulus will keep them up to date thereafter.

I am getting I/O error 32 or I/O error 103

Something on your system has one of the Cumulus files open, preventing Cumulus writing to it (Cumulus needs exclusive access). This may be anti-virus software or something similar. If you are seeing "file access denied", you may have a permissions problem.

I get very large amounts of rainfall shown, or other high readings

Fine Offset stations have a habit of producing unbelievable readings, and Cumulus filters many of these out automatically. You can also use the 'spike removal' settings on the calibration page, and Cumulus will then filter out large changes in readings. Please read the help for how to use these settings. Another possible explanation is that you have chosen the wrong station type in the Cumulus station settings. You should only select the "Fine Offset with UV/Light sensor" type if your station actually has SENSORS for these. Your station may have solar CHARGING, but this is not the same as having a solar SENSOR, and so you should choose the "Fine Offset (WH1080 etc)" type. Typically, stations which do have solar SENSORS have a model number which starts with a '3', e.g. WS3080, and stations without solar sensors start with a '1' or '2'. Selecting the wrong type of station will cause Cumulus to misinterpret the logger data read from the station and hence incorrect readings will result.

Website

How do I set up a website?

The crucial settings are selected on the Internet screen in the Configuration menu.

• On the Sites/Options tab, you must have Auto Update selected if you want Cumulus to generate web pages at the standard interval. Other parameters will depend on your particular set-up, but are explained in the Cumulus Help and in Wiki pages starting with Website_setup and following links as required.
• On the Files tab, you select whether to use the standard Cumulus templates and images, or specify your own templates and destinations.

How do I replace the 'bird' image on my website?

There are several ways to change the image of the 'bird' on the standard Cumulus web page. You will need a FTP tool.

• The simplest way is to upload a new picture to the images folder of your website; the file should be called picture.jpg. Please ensure the image is not too large and bear in mind it will appear on the bottom left of the page; the site data may cover some of the image. As a guide, the default image is 600 x 450 pixels.
• Secondly, you may upload an image using your own file name. Edit the weatherstyle.css file and look for the line background-image: url(images/picture.jpg); around line 9 and adjust as necessary. Upload the edited css file to your website.
• if you wish to remove the image completely edit the weatherstyle.css file and remove the line background-image: url(images/picture.jpg); Upload the edited css file to to your website.

NOTE: It is not recommended that you overwrite the image in your local folder (webfiles\images\picture.jpg) because that gets overwritten when you update to a new build of Cumulus. Ideally your image will be in its own local folder outside the Cumulus structure.

Why does the heading say 'weather weather' ?

The standard first template page contains <h1><#location> weather</h1>, so do not include 'weather' in your station name (this is what the tag <#location> represents, see next answer) to avoid it being duplicated.

How do I change the "Welcome to." on the front page

The Welcome message is controlled within Cumulus. Click on the Station screen in Configuration menu and Edit the Name field within the Location frame to amend what the tag <#location> outputs. The Description field is also used on the front page of the site.

I don't have a solar sensor. How do I remove the solar data from the supplied web templates?

Locate the Cumulus 'web' folder on your PC and edit the following files (there are comments in the html to guide you):

indexT.htm

Remove the following code:

  <!-- Solar data. If you don't have a solar sensor, you may wish to delete everything from here to the next comment -->
  <tr class="td_temperature_data">
    <td>Solar Radiation</td>
    <td><#SolarRad> W/m²</td>
    <td>Evapotranspiration Today</td>
    <td><#ET> <#rainunit></td>
  </tr>
  <!-- End of solar data -->

todayT.htm

Remove the following code:

    <!-- Solar data. If you don't have a solar sensor, you may wish to delete everything from here to the next comment -->
    <tr class="td_temperature_data">
      <td>Hours of Sunshine</td>
      <td><#SunshineHours></td>
      <td>&nbsp;</td>
    </tr>
    <!-- End of solar data -->

yesterdayT.htm

Remove the following code:

    <!-- Solar data. If you don't have a solar sensor, you may wish to delete everything from here to the next comment -->
    <tr class="td_temperature_data">
      <td>Hours of Sunshine</td>
      <td><#YSunshineHours></td>
      <td>&nbsp;</td>
    </tr>
    <!-- End of solar data -->

How do I remove Inside Temperature graph or add solar/UV/sunshine?

Locate the Cumulus 'web' folder on your PC and edit the following file: trendsT.htm

Modify the following code:

    <td class="td_thumbnails"><a onclick='changeImage("images/intemp.png")'><img src="images/intempsm.png" alt="Inside Temperature Graph Thumbnail" width="150" height="100" style="border:0" /></a></td>

• For solar, replace 'intemp.png' with 'solar.png', replace 'intempsm.png' with 'solarsm.png', and change the wording of the value associated with the alt property.
• For sunshine, replace 'intemp.png' with 'sunshine.png', replace 'intempsm.png' with 'sunshinesm.png', and change the wording of the value associated with the alt property.
• For UV, replace 'intemp.png' with 'uv.png', replace 'intempsm.png' with 'uvsm.png', and change the wording of the value associated with the alt property.

If you want to do more than a straight one for one swap see here.

How do I include extra items on supplied web templates?

Open the folder cumulus\web and edit the relevant file named xxxxxT.htm. For example instead of deleting the sections in the remove solar answer, edit their contents. See Customised_templates#Changing_the_Standard_Templates for fuller description.

If you do change the standard templates, take a copy of your new versions, and store elsewhere. The sub-folder cumulus\web\originals has copies of the standard templates from the installed build, do not edit these. When you install a new build of Cumulus, you have an option to replace or not replace the contents of cumulus\web with the new build's standard templates.

How do I upload extra web pages?

See Cumulus help for the Internet Settings screen, or for a step-by-step guide see Customised_templates#What_to_select_on_the_.27Files.27_tab_of_the_Internet_Settings_screen_within_the_.27Configuration.27_menu

What character encoding does Cumulus use for the web pages it generates?

Cumulus 1.9.4 build 1093 changed all the template pages from XHTML 1.0 Transitional using charset=iso-8859-1 encoding to HTML 5 using charset="UTF-8" encoding. It uses this without Byte Order Mark (BOM).

From that build, you can tell Cumulus which of those two encodings to use:

• For standard template names in standard 'cumulus\web' folder, if you replace them with customised templates not using "Universal Character Set Transformation Format — 8-bit" (UTF-8),
  • unselect UTF-8 encode in the web settings frame on the Sites/Options tab of Internet settings screen in Configuration menu.
  • Cumulus will then, as in earlier builds, use iso-8859-1 encoding.
• For extra templates, the Files tab of the Internet settings screen in Configuration menu has the option to choose which of the two Cumulus encodings to use. See Wiki article referenced in previous answer.

Note that since Cumulus 1.9.4 build 1078 there has been an option on the NOAA Setup screen in Configuration menu to specify whether character set utf-8 encoding is to be used for those reports.

Why does a standard gauges web page have text where it should show gauges?

If a standard Cumulus 'gauges.htm' web page displays like this then either

1) (Most Likely) The weather station owner has not loaded the required files/folders onto his/her server;

• The gauges graphics require the 'images' subfolder (see next answer), containing the script and many images to be pre-loaded in the 'dbimages' subfolder.
• All these should exist within the destination folder that holds the HTML files as instructed in the Cumulus Help ('setting up your website' page)
• Also explained in Simple Website setup on this Wiki.

or 2) JavaScript is not enabled (or not available) in the browser being used to view the page (if not enabled, this can be switched on in either 'Options', 'Preferences' or 'Settings' depending on browser). Note that Firefox version 23 has removed the ability to change this in Option preferences, so ignore this solution in that browser.

or 3) You are using a browser add-on such as 'NoScript' (over 2 million use this) which requires you to explicitly turn on JavaScript for each web site you visit within the 'NoScript' options. (This sort of add-on may be used to restrict advertising or tracking of your actions, or for security against unwanted processes being started by sites you visit).

Why are there no graphs on my standard trends web page?

Either 1) You have not created an images sub-folder (within your folder that holds web pages) as instructed in the Cumulus Help ('setting up your website' page) - also explained in Simple Website setup. In this case, the bird image will not be appearing in the bottom left corner of your web pages.

Or 2) You have switched off Include Standard Images on the file tab of the Internet dialogue of the configuration menu. In this case Cumulus believes you are working in a non-standard way, and does not automatically upload the graphs (nor moon image).

What is the size of the standard Cumulus update?

The default is that all of the standard pages and standard images are uploaded on each update at whatever standard update frequency you select.

In total for version 1.9.2, it's about half a megabyte - about 100kB for the pages (about half of that is the gauges.htm page with all the detailed wind plotting points, and half the other pages) and 400kB for the variable images (moon phase, some gauges images and trend graphs - the exact size of latter can vary if you change the period they cover).

Version 1.9.3 adds the monthly records page which contains 12 months worth of a lot of data, and adds 25kB to every update (although usually very little changes between updates).

The NOAA monthly and annual pages are uploaded once a day, that is another 8kB for a full month and full year, obviously less at the start of a month/year.

Optional extras This excludes the realtime.txt file, this is less than 1024 bytes in size. It also excludes any additional file transfers you may add (e.g. dayfile.txt a file that keeps growing in size or files required by external sites that are no more than a few kB).

How do I upload my own pages or files once a day?

Cumulus allows you to specify a command (with optional parameters) that will be actioned just after daily rollover. The command is entered in the External programs frame at the bottom left of the Internet Settings screen. The box is labelled Daily. Click the Cumulus Help button for guidance. For example you could type 'c:\cumulus\daily.cmd' in the box labelled Daily.

This could be used to upload the pages with the longer term extremes (as your monthly, annual and all-time extremes may only change a few times a month or even less frequently) and so reduce the upload burden at the standard uploading frequency. To achieve this you would use the content of that example file 'daily.cmd', in the default Cumulus folder, to call your own file transfer tool for those infrequently changing pages. Remember to also unselect Include Standard Files on the 'Files' tab of 'Internet settings', and list the templates on that tab, selecting Process? for all of them, but only selecting FTP? for the other frequently changing pages that are still to be uploaded at the standard interval. You may find help on the forum or elsewhere on this wiki for the FTP call and for 'Files' tab settings.

It can also be used for the optional files mentioned in the previous answer. For the daily command specified above, in the default Cumulus folder, add a file 'daily.cmd' that contains (if you host your own server using 'XAMPP'), 'copy c:\cumulus\data\dayfile.txt C:\xampp\htdocs\weather\daj\' for example to enable you to use the Annual Day-by-day Summary tool. (Uploading if you do not host your own server is described at upload dayfile but basically you swap the copy command for a FTP command).

The 'real time wind data' gauges on the standard gauges page aren't working

These require a realtime.txt file to be uploaded by Cumulus. Tick the "Enable Realtime", "Enable Realtime FTP" and "Enable realtime.txt FTP" boxes on the internet settings screen. If the gauges still do not work, check that the realtime.txt file is being uploaded to the correct place. If it is not, it is likely that you have specified an incorrect 'ftp directory' in Cumulus. If your 'normal' pages are being uploaded correctly, but realtime.txt is not, then it is likely that you simply need to leave the ftp directory blank (but see the note below first).

A possible cause for this problem is that your web space provider does not allow .txt files to be accessed. For example, the free hosting provider 000webhost.com do not.

I'm using the supplied web pages, and get lower case in places where I want upper case

It's in the CSS. Go to the webfiles sub-folder of your cumulus installation, edit weatherstyle.css and find lines like: "text-transform: lowercase;" and remove them. Use FTP tool to replace the weatherstyle.css on your website.

My web pages have things like <#location> in them

You’ve edited your templates with something like Dreamweaver, and it’s changed the angle brackets on the Webtags to "&lt ;" and "&gt ;" - you need to change them back to < and >. These may look the same when viewed in your browser, but you can see the difference if you 'view source'

Alternatively, if the web templates are listed in cumulus.ini (and for the first 10 appear on the files tab of Internet dialogue of Configuation menu), the Process option must be ticked for the web pages generated by Cumulus to have values replacing the Webtags. Otherwise at each web update, Cumulus will generate web pages the same as the templates.

My web pages are empty

If empty web pages are being uploaded to your web site (i.e. they report size of 0 kB, but do not produce 'error 404 - page not found' message), and your browser shows that their modification date is recent (see next FAQ), then it is likely that the Cumulus processing of templates is failing:

• Either (since build 1093) because the character encoding used in the relevant template does not match the character encoding (UTF-8 or iso-8859-1) that (for standard named templates) is specified in Web Settings frame as shown about half way down on this screen extract.
• Or you have edited/customised the template and added an incorrectly specified Cumulus webtag that has caused Cumulus processing to abort for that template. If you stop cumulus you can use a text editor to open the latest diagnostic file. Look at entries time-stamped just before the hour and repeated at your auto-update interval (also about half-way down in screen image above). You might find a message like "Error processing C:\web\indexT" (i.e. mentioning whichever template is at fault) followed by a brief hint as to the nature of the error.

My web pages have obsolete web tag values in them

If the information showing on your web pages is out of date, then it must have been working before, so you have made a change somewhere.

• Most browsers will display 'page information' that tells you when the page was last modified (by querying the web server).
  • if the page was recently modified,
    • then the next item to investigate is the template file; a template file contains Cumulus web tags and the 'process' that Cumulus does to create a web page involves reading text from a template and when it finds a web tag it inserts the latest value in as it creates the page. Therefore if there is no template file, Cumulus can not generate a new web page and will just upload the old local copy of the web page.
  • if the page was not recently modified,
    • maybe you are not running Cumulus, so it is not updating.
    • maybe your file transfer is not working, turn ftp logging on for technical output, and look for any filenames and any 'successfully transferred' messages.
    • maybe your 'internet settings' screen has accidentally been changed, see Cumulus help for simple instructions. If you took a backup of cumulus.ini you can stop Cumulus, rename the current file and copy your cumulus.ini backup back into the 'cumulus' directory containing the Cumulus program.
    • maybe your web server provider has changed something.

Running a web server on the same PC as Cumulus

If you do not have a web site, or run a web server locally (same PC, or on your local network), you can get Cumulus to generate/copy html or image files locally instead of using FTP to place them remotely. You'll need to list the (source) file including paths on the files tab of the internet settings, and specify a destination path and file name for the remote file in each case. Don't tick the FTP? box for standard cumulus pages (the exception is for a local web server and any non-standard web page that attempts to read using a script a local file such as dayfile.txt as this does need FTP to generate the server-based web page). For the standard images, you can supply a folder name (specify on the same screen), and they will all get copied there. Set everything else up as if you were using ftp, but don't supply a host name etc (except for exception already mentioned). See here for greater detail.

There's a limit of 10 files on the files tab, but you can increase this to 20 files in version 1.9.2 (in version 1.9.3 it is 100 files) by editing cumulus.ini, with Cumulus stopped. Follow the format of the entries for first 10 files.

Error Codes generated by FTP or Winsock

You should be able to look these up on the web. Try Here

How do I configure Cumulus for Secure FTP (SFTP/FTPS)?

Cumulus doesn't support Secure FTP. You can configure Cumulus to invoke an external program like WinSCP, as described here: SFTP article

Directory related problems in FTP

The following pointers should help:

• All universal resource locator (url) references are case sensitive. So if your FTP server directory is public_html, then 'Public_HTML' will not work!
• On the Internet settings screen in Sites/Options the optional Directory parameter required is the path from your FTP root, to where the web pages are to be stored. Click the Help button for full explanation, or search the support forum as many people have found this is the hardest parameter to get right.
• The standard pages are uploaded after a 'change directory' attempting to select the directory you specified in Sites/Options; if this fails, the files will still be uploaded but to the FTP server root. So some mistakes do not matter because if no change of directory was actually required, these pages will be uploaded correctly.
• Any files you specify for uploading at standard update frequency are uploaded between standard pages (if 'Include Standard Files' selected) and standard images (if 'Include Standard Images' selected), and in 'remote filenames' you specify the path including any web site directory, so there is no call to 'change directory'. In this case, if that web site directory is invalid, the upload fails.
• The standard images for gauges and trends pages are uploaded after the standard pages, (and any pages you specify for uploading,) by performing a second 'change directory' this time fixed at 'images'; if this fails, the files will still be uploaded to the current web site directory (FTP root or the directory you specified in Sites/Options).
• If you have enabled Realtime, the realtime.txt file is uploaded without doing a change directory, by appending "/realtime.txt" to the directory on the Internet settings screen in Sites/Options. In this case, if the web site directory is invalid, the upload fails.
• On the NOAA Setup screen the optional Directory parameter required is the full path from your FTP root, to where the NOAA report pages are to be stored. (It is totally independent of the directory on the Internet settings screen in Sites/Options). Click the Help button for full explanation. Like realtime.txt, the upload is by appending the filename for the report to the NOAA directory and will fail if that directory is specified wrongly.

See Setting up your website in Cumulus help for a simple guide to the subfolder structure you need to create and the list of files that need to be uploaded manually when first installing a website. Or see Website_setup for all the options including customised pages.

My standard web pages are uploading but the uploading fails for images, realtime and/or NOAA reports

See previous answer, you have probably got your web pages in the default FTP directory of your web site, but specified the wrong directory on the settings screen. Turn on the FTP logging in the configuration menu to see the technical detail. You should have an FTP tool that you used to upload the 'static' files required on your web site, and that will help you to see what is your site's root directory for file transfer uploads, and therefore any relative directory change you require.

What file-names does Cumulus use when processing and uploading files to my web site?

FTP Process

Cumulus use two slightly different processes depending on if the file is part of the supplied 'standard' web site, or an extra file you have specified on the Internet Settings|Files configuration dialog. For each of these processes there is an further variation depending on whether you have enabled the Use FTP rename option. This graphic shows the various combinations of file-names used for each step of the process. For the standard files, you can substitute any of the file names for indexT.htm, e.g. trendsT.htm

For more details of Cumulus Process see here.

Selecting a Weather Station sensor site

A simple guide is at uk.sci.weather newsgroup, note this advises against roof mounting. An attempt to compare the conflicting siting standards that apply across the world is included in a portable document format guide from Campbell Scientific. For more advice see the website of your local Meteorological Bureau, an educational place (e.g. in USA see Cornell University), the World Meterological Organisation (WMO), or a specialist organisation (e.g. in UK see Royal Meteorological Society rather than the Met Office web site).

Modern Stevenson Screens are uPVC constructed with a black interior (so they do not radiate heat onto the sensors) and a white exterior (so they reflect as much radiation as possible). There is a lot of discussion on the Homebuilt forum about different approaches to improving measurements, and the problems with out of the box instrumentation from the different manufacturers.

If you are contributing to an external site like APRS/CWOP, Weather Underground, PWS weather, Weatherbug and/or WOW, see guidance from these organisations re instrument placement.

Note: Some stations have all sensors in one unit, positioning of these is a compromise between the ideals below for each sensor.

Where should I position the wind sensors

The side labelled 'North' on the wind vane mount should face True North, remember that the magnetic north deviation from true north varies from year to year, see details on maps or online. Most wind vanes have a large surface that follows the wind and a thin end that points where the wind comes from, it is the latter direction that is reported.

In the UK, the standard climatological measuring height is 10 metres. Advice varies on whether you should apply a correction factor for any lower height. Cumulus allows you to apply such a factor to either just wind speed, or wind speed and gust speed, by using the Calibration screen within the configuation menu. In the Cumulus Help it recommends that you also adjust wind chill - in practice this means ask Cumulus to calculate wind chill by selecting this in the settings frame on the station settings screen accessed from configuration menu (i.e. ignore any wind chill output by your weather station).

If you are mounting near a building of height 'h' above ground level, ideally the wind sensor should be at a height of '1.5 times h' above ground level. If you are positioning away from a building or tree (or other object) of height 'h' (or the mean height of several objects is 'h'), then the distance away depends on which standard you are trying to meet, and can vary between 1.5 and 3 times 'h'.

Where should I position the rain sensor

The WMO says the rain gauge should at a distance away of 2 times the height of each nearby object (buildings, trees, walls, solid fences etc.) and just high enough off ground level to avoid possibility of splashing. You can experiment, but for amateurs, no more than a metre off the ground (or roof if mounted above it) and at least a metre from any chimney, wall or solid fence whose height exceeds that of the sensor seems good enough for most gauges. See Rain measurement or your local offical organisation.

How do I protect my rain gauge against spiders or other natural problems

There is a lot of discussion on the Homebuilt forum. In terms of siting, it is important to position your rain gauge where you can safely get to it.

How do I get good temperature and humidity measurements

The international standard states ambient air temperature/humidity is measured at 1.25 metres above ground level, above soil or grass not paving, protected from direct sun radiation (and direct rain), unless you are measuring soil or ground temperatures. The height is important for derived values as an air frost is defined as a temperature below the freezing point for water at this height, and the count of these is a standard reporting requirement in some countries.

If you are using a Fine Offset sensor, the thin depth of the thermonmeter/hygrometer (transmitter) should face where your console (receiver) is, for maximum transmission strength/distance, with the wide face at right angles to the transmission route. (Although if you use a model requiring a radio time signal, you will probably be trying to optimise that instead).

Pressure

Varies with altitude and temperature, but no significant variation with spatial position with regard to nearby fixed bulky objects. Often measured indoors, do not mount above any heating or cooling system as there temperature may be particularly variable, and try to avoid any forced ventilation or extraction as such air moving systems could have different pressures on intake and outlet sides. Equally operation in close proximity to opening doors/windows or to fast moving (road or railway) vehicles or tunnels can distort readings.

Solar

One would expect solar sensors should be positioned for maximum unshaded exposure to sunlight throughout the year, but again the forum contains advice for specific makes.