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{{Template:Version badge Mx}}{{Version badge 1}}This Wiki page applies to both Cumulus flavours. [[Category:Files_with_Comma_Separated_Values]]
Cumulus maintains a daily log file that holds the highs and lows of each day, as well as a few other nuggets of information. The figures contained in the file are used for the 'This period' display accessed from the '''View''' menu and to build any graphs based on daily values.


As part of a redevelopment of Wiki, this page has been simplified, by moving some content to new pages. Old links in the support forum, that were to content no longer on this page, will bring you here.
== Viewing the daily log ==
To view the whole daily log use the ''dayfile.txt'' command in '''Edit''' menu. This is how you view, and optionally edit, the dayfile.txt from within Cumulus. If you upload the file to your web site, then see [[AnnualDataSummary]] for information about ways to show values for a particular weather criterion in a calendar like display.


'''Content previously on this page has been moved as follows''':
To view a summary of dayfile.txt for a month, calendar year or selected period, use ''This month'', ''This year'' or ''This period'' within the '''View''' menu. By default, these load the details for the current calendar month, the current calendar year or yesterday; i.e. in all cases they exclude the today details that are not stored on dayfile.txt until the end of day rollover.
* Explanations about Cumulus terminology can be accessed from [[:Category:Terminology]] page
* Each line in this file represents one day, but the start time need not be same for all fields,
** so please see [[Meteorological_day|Meteorological day]], and [[today.ini]] for more details about that
* Advice regarding editing this file has been moved to [[Amending dayfile]] page, this also covers date-separator issues and dealing with missing or corrupted lines
* General advice about Cumulus files with a '''.txt''' extension has been consolidated on [[:Category:Files_with_Comma_Separated_Values]] page
* Advice about correcting any rogue extreme figures inadvertently stored in this file has been consolidated in new [[Correcting Extremes]] page
* If some lines in your file have fewer fields than other lines the advice has been consolidated on [[Calculate Missing Values]] page
** For MX there is a [[Calculate_Missing_Values#CreateMissing.exe|Create Missing Utility]], which checks spot readings in the [[Standard_log_files|MMMyylog.txt]] files, adds any missing derivative spots (e.g. heat index) and uses these figures to recalculate daily derivatives and uses those to replace missing fields/lines in dayfile.txt
** For the legacy Cumulus, there was a [[Amending_dayfile#Create_Missing_on_legacy_dayfile_editor|dayfile editor with create missing option]], that performed equivalent function
** If you import historic data from before you started using Cumulus into [[Standard log files]],
** then see [[Calculate Missing Values]] page for how to generate new lines in dayfile.txt
* Cumulus MX is more fussy, than Cumulus 1, about various formatting issues, see below, also see [[Migrating_from_Cumulus_1_to_MX#dayfile.txt]] section for more advice


The content that remains on this page is summarised by the table of contents that follows.
== Dealing with rogue measurements ==
Cumulus provides via '''Configuration''' menu ''Calibration'' screen the ability to screen out spikes in data picked up from your weather station. See Cumulus help screen if you decide to use that to cope with some spikes. But some rogue values may be within the accepted all-time range, but just not really applicable to that particular day.


=About this file=
If you discover a rogue measurement (perhaps the wind affected your tiping bucket rain gauge or your weather station just reported a corrupted value), on the day it occured, see [[today.ini]] or [[FAQ]] for further advice.


* This Wiki page describes one of the [[:Category:Cumulus Files|files]] not included in any release download.
If the rogue measurement is discovered some days after it occured, then in many cases it will have affected your highs and lows for the current month, month-by-month, current year, and/or all-time. As first step you should update the appropriate field in the row for the affected date in dayfile.txt. Once ''dayfile.txt is correct'' the Cumulus editors will allow you to:
* This daily summary file (Steve Loft shortened that to "day" plus "file") uses a ".txt" extension, and is essentially a plain text file in CSV format.
* update the highs and lows in [[Alltime.ini]] by choosing ''all time records'' from the '''Edit''' menu. See [[Alltimelog.txt]] for current and previous values to help you know what rogue value to hunt for and know what the high/low value was before the rogue affected it.
** CSV stands for "Comma Separated Values", but in the Cumulus context the field separator can be other characters including ";" or "|"
* update the highs and lows in [[year.ini]] by choosing ''This year's records'' from the '''Edit''' menu.
* The file is created in [[data folder|data sub-folder]] of your Cumulus installation when Cumulus needs to store its first line in this file.
* update the highs and lows in [[month.ini]] by choosing ''This month's records'' from the '''Edit''' menu. See [[Diags]] for current and previous values of high or low in the current month or the immediate preceding month if the rogue was recorded less than 10 days ago.
* Cumulus MX reads the whole of this file into an internal array (stored in RAM) each time you restart the software,
* update the highs and lows month-by-month in [[monthlyalltime.ini]] by choosing ''Monthly records'' from the '''Edit''' menu. Click the ''Help'' button for specific instructions on using ''Reset'' and the two ''Copy'' column header buttons in this ''Monthly Records (Highs and Lows) Editor'' to action all rows.
** Please see [[Amending_dayfile#Warning_if_editing_outside_MX|here for implications]]
'' '''Note''' in each of above 4 editing screens you can:
** Therefore MX users who move to a different location should archive the old "dayfile.txt", to avoid any discontinuities in any graphs plotted from active file
# see the currently stored extremes, and optionally ''Reset'' (row by row) to pre-editing value and timestamp.
# load the dayfile.txt to view extremes derived from those figures (after your correction of the rogue values) and
# optionally ''Copy'' (row by row) the logged values (and associated date/time information) into the relevant .ini file.
# click the ''Help'' button for detailed instructions on using ''The Records (Highs and Lows) Editors''.
# store your revised figures by clicking ''OK'' (or abandon all your edits by clicking ''Cancel'').
(Each of these screens is a text editor, and works best when at full screen).''


Ideally, you will subsequently try to edit the rogue data for the particular time it was logged; see [[Monthly_log_files#Correcting_any_logged_data_problems]], but correcting the daily summary in dayfile.txt must always be the priority.


([[Speciallog.txt|speciallog.txt]] is another log file that contains all dates in a single file, as do all the [[:Category:Ini_Files|.ini files]]).
==Editing in Cumulus==
The last command in '''Edit''' menu is ''dayfile.txt''. This is a text editor, and works best when at full screen.
Click the ''Help'' button for detailed instructions. Cumulus Help is comprehensive.
You can use this editor to:
*correct individual values by overtyping,
*use '''delete''' key to remove an entire day (e.g. if you get a 'duplicate' error message),
*use '''insert''' key to add one or more missing rows (complete days) manually,
*use '''Create missing''' button to insert missing rows (complete days) by reading from [[Monthly_log_files]] and automatically calculating the best approximations for each field for those missing days.
If you do have a 'duplicate' error, you need to decide which row to ''delete'', and whether to copy any values from that row into the row you are keeping to ensure the correct extremes are retained.


For ''Create missing'' a list of inserted records is produced in [[dayfileeditlog.txt]]. If just some fields are wrong in a particular row (meteorological day) on day file, then there is a [[Monthly_log_files#Using_Monthly_logs_to_deal_with_shorter_.28or_incomplete.29_dayfile.txt_records_for_particular_dates | workaround]] as at all current versions (up to 1.9.4) you can only use 'Create missing' to read from the [[Monthly_log_files]] if the whole day (a row starting with a date) is missing in ''dayfile.txt''.


==How Cumulus Creates and Updates this file==
The procedure for importing, and processing, pre-Cumulus observations is explained in [[Monthly_log_files |this Wiki topic]].


* Cumulus reads values supplied by your weather station, (either directly while Cumulus running, or for some weather station types can read historic data during catch-up on restarting Cumulus)
'''Note for version 1.9.3 only:''' Create missing might in some cases be affected by a bug in 1.9.3 that can cause incorrect date order for records (dayfile.txt uses dd/mm/yy or dd-mm-yy and all records should be in ascending chronological order)
* Cumulus converts them to the units you prefer,
* Cumulus applies any calibration (multiplier and offset) you have set,
* For a sub-set of those readings (perhaps those every minute if readings are collected every 10 seconds), the spot values of source items like temperature, humidity, wind speed, can be used in calculations of derived items like "wind chill", "dewpoint" and "feel-like" temperature.
* Cumulus then sees if the resulting soource, or derived, value implies [[:Category:Ini Files|any extreme records file]] needs to be updated
** Daily extremes are held in [[today.ini]] and that is main source used when a new line is added to "dayfile.txt"


'''Note for versions 1.9.2 or version 1.9.3''' There is a bug in these versions in that 'Create missing' inserts 'heating and cooling degree day' values the wrong way round.


==Why this file should be backed up==
Any bugs are believed fixed in version 1.9.4.


* This file contains daily extremes, the accuracy of those daily extremes depends on the interval between the spot readings that are used as explained above.
==Manipulation outside Cumulus==
* If the file is corrupted, and not regenerated from a back-up, the only source of spot readings is the [[Standard_log_files|MMMyylog.txt]] files, and their interval might be only every half an hour (it has to be an exact fraction of an hour).
The file is <tt>data\dayfile.txt</tt> within the directory holding the Cumulus excutable, it can be viewed in a text editor, or imported into various database systems, or imported into spreadsheets, to manipulate as you wish. Just remember that Cumulus updates it as part of the rollover process, so never attempt to work on it either when Cumulus has just been restarted and is checking/updating the logs, or around the midnight/9am/10am local rollover time when Cumulus is writing a new row.
* As explained [[Monthly_log_files#Enhancement never implemented|here]] minima and maxima between such logging intervals are not recorded by Cumulus software
* Thus it is worth backing up this file, to another device than that running Cumulus, on a regular basis, probably a few times a week, to ensure this precious data is not lost if your device running Cumulus has a malfunction (or is damaged), or an electrical blip (or mistake by you) causes corruption to the original file,


Cumulus does periodically copy this file within the installation, but the copies are only kept for a limited time, and are on the same physical storage device, and so your main file is corrupted you might not be able to access the Cumulus back up or might not be able to go far back enough to find a file that has not been corrupted:
'''Tip''': Take a copy of the file before you work on it outside Cumulus (perhaps call the copy 'dayfile.csv' so Windows can recognise its structure).
* The file is backed up when MX is restarted into a date/time stamped sub-folder of the [[Backup folder|'''backup''' folder]]
*The file is also backed up (to a date/time stamped sub-folder within '''daily''' sub-folder of that backup sub-folder) during the end of day process, but (depending on the release you are running) the back-up copy may, or may not, include a line for the previous day (the line that is appended in the same end of day)


Retention of these back ups:
'''Note''': Since new versions/builds can add to number of fields, Cumulus will accept lines of various lengths without the more recent fields at the end. (Additions for the last few builds only are indicated below, you can explore details of earlier versions via the official [http://sandaysoft.com/products/cumulus product] page).
* [[File:Badge vMx.png]] MX only keeps the last 9 of the date/time stamped sub-folders.
* [[File:Badge v1.png]] Legacy Cumulus 1 only keeps up to 8 of the date/time stamped sub-folders.


== Specific issues for MX ==
'''Important Rules''':
* The (meteorological) date format uses ''two digits for the year''. Edit this file using an editor that treats all fields as text (a text editor or a spreadsheet program that can be instructed ''not'' to recognise special field types). For software (e.g. Excel) with default of recognising formats, ensure that such recognition is turned off, as it is likely to change the dates to either a number representing days since e.g. 31 Dec 1899, or to have four figure years, and then Cumulus will no longer be able to use the log file. (Also the month must be the middle figure, USA convention cannot apply within logfiles).
* Times are in ''format hh:mm''
* Most value fields are in ''real number format x.y'' using your system decimal notation, a few (e.g. bearings, solar, humidity) are ''integers'' (see [[#List_of_fields_in_the_file]]). Whilst an integer can be used for a real number field, decimals are not allowed in an integer field.
* If you insert a ''lowest or highest value'' into a day, where there was none before, insert a ''timestamp'' too, as a dayfile.txt row is only accepted by the Cumulus editor if a value and any related timestamp are either both present or both absent. (Use a timestamp of your rollovertime 00:00, 09:00 or 10:00 if you have not looked up the precise time).
* Nulls ',,' are not allowed in the line, so if you do not know the value for a particular field within the line, then type in a zero for integer values and an extreme with opposite value (e.g. -999.9 for a signed decimal maximum, and 999.9 for a decimal minimum) for decimal format (replace the full stops with your decimal separator).
* Make sure that any editing does not create any ''blank lines'' in the file.
* All rows must ''start with date'' and include some of the parameters listed ''in correct sequence''.
* Rows can vary in length but only by missing off ''fields at the end''.
* The row terminator normally expected is ''CRLF'', ensure any external editor does not change the terminator.


WARNING: It is important to note that some releases of MX are very fussy about consistency in all lines of '''dayfile.txt'''. Earlier releases tended to have better compatibility with the legacy software. Subsequent releases expected every line to be expressed exactly as specified in the locale. MX in its latest release is trying to cope better with inconsistent date separators.
==List of fields in the file==
*Alternative lists:
**A version of this list with spreadsheet column letters can be downloaded from the support forum [http://sandaysoft.com/forum/viewtopic.php?f=18&t=8690 here],
**the appropriate list of fields for your installed build is stored as dayfileheader.txt within the folder that contains your Cumulus executable.


Date field: Cumulus 1 (C1) did not care what character (or characters) separated the day, month, and year elements of the date field. MX insists that the same character (or characters), as defined in the locale, is used for all lines in file.
The field number (starting from zero to be consistent with index used for arrays in programming languages like JavaScript) with description and cross-references to further explanation:
* 00: Date as ''2 figure day [separator] 2 figure month [separator] 2 figure year'' - the separator is that set in the windows system short date format (see [[setup]])
* 01: Highest wind gust
* 02: [[Wind_measurement#Wind_Direction | Bearing]] of highest wind gust (integer)
* 03: Time of highest wind gust
* 04: Minimum [[Temperature_(and_humidity)_measurement#Cumulus_Calculated_Parameters | temperature]]
* 05: Time of minimum temperature
* 06: Maximum temperature
* 07: Time of maximum temperature
* 08: Minimum [[Pressure_Measurement | sea level pressure]]
* 09: Time of minimum pressure
* 10: Maximum sea level pressure
* 11: Time of maximum pressure
* 12: Maximum [[Rain_measurement#Rain_Rate | rainfall rate]]
* 13: Time of maximum rainfall rate
* 14: Total rainfall for the day
* 15: [[Average temperature]] for the day
* 16: Total [[Windrun | wind run]]
* 17: Highest Average Wind Speed
* 18: Time of Highest Avg. Wind speed
* 19: Lowest [[Temperature_(and_humidity)_measurement | humidity]] (integer)
* 20: Time of lowest humidity
* 21: Highest humidity (integer)
* 22: Time of highest humidity
* 23: Total evapotranspiration
* 24: Total hours of sunshine
* 25: High [[Heat index]]
* 26: Time of high heat index
* 27: High [[Apparent temperature]]
* 28: Time of high apparent temperature
* 29: Low apparent temperature
* 30: Time of low apparent temperature
* 31: High hourly rain
* 32: Time of high hourly rain
* 33: Low [[wind chill]]
* 34: Time of low wind chill
* 35: High [[Temperature_(and_humidity)_measurement#Cumulus_Calculated_Parameters | dew point]]
* 36: Time of high dew point
* 37: Low dew point
* 38: Time of low dew point


Real number fields: MX uses the '''locale''' to decide what character (decimal comma or decimal point) separates integer and decimal parts of numbers. Every line of the file must be consistent in use of integer/decimal separator. C1 used the '''Region''' settings in Microsoft's Control Panel to determine how to store (and output) numbers for you, but (except if ''list separation character'' was comma) was fairly tolerant when reading old data in files. At the time of writing this, it was proposed the next major release will force this file to use decimal points (full stops not commas) regardless of locale. This proposal may or may not happen, the point is that information here might be incorrect for the release that you are using.
The next 3 entries were added in version 1.9.2 Build 1004
* 39: Today's dominant/average wind direction (integer)
* 40: [[Heat/cold degree days and Chill hours | Heating degree days]]
* 41: [[Heat/cold degree days and Chill hours | Cooling degree days]]


Time-stamp fields: MX insists on HH:mm format being consistently used in every line of file, C1 did not care what (non-space, non-field separator) symbol separated the minutes from the hours.
Added in version 1.9.3 build 1036

* 42: High solar radiation
Number of fields: The number of fields in the file increases in various versions as shown in [[#List_of_fields]].
* 43: Time of high solar radiation
* C1 will accept (as did Cumulus 2) any line with 15 to 45 fields in it. This is because the earliest version only stored 15 fields, as C1 was developed fields were added (as shown in field list) until there were 45 fields.
* 44: High UV Index
* Each release of MX expects a particular number of fields in each line of file; MX has added fields as the software has developed, and it even (as shown in field list) inadvertently added 2 fields later removed. The difference is that MX (for some functionality from release 3.4.5, for all functionality from release 3.9.5) reads the whole file into an internal (RAM held) array with a fixed number of elements, therefore every line ends up with same number of fields when written back into file.
* 45: Time of high UV Index
** If you have some lines in your file that were created by an earlier release of Cumulus, and so have less than whatever is the current number of fields for the release you are using, there is a utility to run that will create a new dayfile.txt with all fields populated, please see [[Calculate Missing Values]] page. Please ensure you use the right version of the "Create Missing" utility mentioned on that page as it also get upgraded when fields are added, and it uses various software libraries contained within .dll files specific to a particular CumulusMX.exe release.

==How to view or edit this file==

The detailed information has been moved to [[Amending dayfile|viewing/editing '''dayfile.txt''' page]].

An editor has been included within recent Cumulus releases of each flavour:
* [[File:Badge vMx.png]] Available from release 3.4.5 (13 Mar 2020): In [[MX_Administrative_Interface#The_Data_Log_Viewing_and_Editing_interface|the interface]] go to '''Data logs''' menu and select ''Dayfile''
* [[File:Badge v1.png]] Available from version 1.9.2 (5th October 2011) to final legacy release: On Main Screen from [[Cumulus_Screenshots#File.2FEdit.2FHelp_Menu|'''Edit''' menu]] select ''Dayfile.txt''
**'''Note for obsolete version 1.9.0 to 1.9.3:''' There is a bug in these versions in that 'Create missing' inserts 'heating and cooling degree day' values the wrong way round.
**'''Note for obsolete version 1.9.3 only:''' Create missing might in some cases be affected by a bug in 1.9.3 that can cause lines to be stored in incorrect date order (dayfile.txt uses dd.mm.yy, dd/mm/yy or dd-mm-yy, for its date field; and all lines should be in ascending chronological order)
**There are no known bugs for dayfile.txt handling in version 1.9.4 builds 1086 to 1101. Build 1099 is the standard stable final release of Cumulus 1 for most weather station types, 1100 and 1101 are for specific weather station types.

Please note that the editor in Cumulus 1 allows you to change the date, as well as all the other fields, although the lines must be kept in ascending date order to avoid errors when subsequently reading the file.

The MX editor does not let you change the date, you can only change other fields or delete an entire line, so you have no control over the order of the lines in the file.


==Reading the file==

See [[Daily Summary]] page for a full discussion of ways, external to Cumulus, to read this file.

Apart from the viewing/editing options just described, Cumulus software reads this daily summary file in vaCumulus 1 does not actually number lines, however it does count lines as it reads them, so if there is an error when it reads the file, the original Cumulus will report the line number (numbering from 1) where it first found an error (line numbering uniquely identifies the line, even if a date is duplicated, or a line feed has been deleted so two lines are merged).rious other circumstances depending on the release you are running.

* [[File:Badge v1.png]] The legacy software only reads the file when the Cumulus user makes a specific request, in normal operation the existing content is ignored:
** The legacy Cumulus has a number of [[Cumulus_Screenshots#View_data|screens for viewing data for various periods]], to populate these screens Cumulus has to read all of the [[:Category:Files with Comma Separated Values|Files with Comma Separated Values]] as the derivatives shown generally do not match the extremes tracked in [[:Category:Ini Files|.Ini files]].
** The '''Select a graph''' feature also uses all of the [[:Category:Files with Comma Separated Values|Files with Comma Separated Values]].
** The end of day action uses a simple "append" instruction, so it does not need to read the file
* [[File:Badge vMx.png]] As already mentioned, MX reads the entire '''dayfile.txt''' file when it is first started into an internally held array. That internal copy was introduced in release 3.9.2 - b3097 (7 Dec 2020), it was needed to drive the [[Highcharts_-_Historic|'''historic charts functionality''']]; both in the [[MX Administrative Interface|interface]], and the example included [[New Default Web Site Information|Historic Charts web page]].
** From release 3.20.0 - b3200 (21 Aug 2022) there is a '''This Period Highs and Lows''' web page (accessed from ''Records'' menu) which is similar to the ''screens for viewing data for various periods'' except that the extremes it shows match those tracked in [[:Category:Ini Files|.Ini files]].
** From release 3.20.0 - b3200 (21 Aug 2022) there is an option to '''Reload dayfile''' in a ''Utils'' menu, this updates the internal held array by reading the file again; essential if an edit has been made to the file.

==Line numbering and Error messages==

Cumulus 1 does not actually number lines, however it does count lines as it reads them, so if there is an error when it reads the file, the original Cumulus will report the line number (numbering from 1) where it first found an error.

Cumulus MX stores the contents of the file in an internal two dimensional array. The outer dimension is identified by numbering (from zero) what were lines in the file. The inner dimension has that line number as element zero, and the fields taken from file are therefore numbered from one.

Obviously, line numbering uniquely identifies the line, even if a date is duplicated, or a line feed has been deleted so two lines are merged in the file. This is why you will see line numbers quoted in any error messages related to this file.

Some of the editors you may use to view/edit the file may number the lines (in some cases always, in others as an option). If you have seen an error message, then to correct the file you need to use a tool that does number the lines in order to find where the correction is needed. Error messages report just the first error found, so check subsequent lines in case they have same error.

= List of fields in dayfile.txt =

For your installed build please see ''[[dayfileheader.txt]]''. This file identifies all the fields in each line of the '''dayfile.txt''' file in the release you are running.

That file has changed location from release 3.20.0 - b3200 (21 Aug 2022), it is now in [[data folder]], for Cumulus 1 and all earlier MX releases it was in same directory as the Cumulus executable.

As explained earlier, the number of fields in a line has (with one exception when fields were added in error) increased as the Cumulus software has been developed. The table below therefore groups the fields under labels that indicate which version/release introduced them.

==Field numbering==

The table below was first created when the only flavour of Cumulus software available was what we now call the legacy Cumulus 1. Back then the fields '''were''' numbered starting from zero. This reflected the way fields were identified when processed as elements of an single-dimension array variable representing a line.

The old numbering from zero had two advantages:
# It stressed that the date field was different to the rest, all other fields were either values or time-stamps
# Numbering starting from zero is consistent with standard indexing used for arrays in programming languages (like JavaScript), so the number shown '''was''' the number to quote in any scripts where a Cumulus 1 line was converted to an array, and you needed to address a single field.

Please note the list of fields has been rewritten especially for MX. As part of the rewrite, the fields have been renumbered, in some forum posts you might see references to old numbering, in others to new numbering. As explained [[#Line numbering and Error messages|above]] the fields are now numbered starting from 1 to fit in with an internal array created when the log file is read, the processing code adds a line number in front of the date field on each array 'line' it holds.

== Information shown in the table ==

* The date '''is supposed to''' be a unique identifier, the same date should not be repeated in another line, however Cumulus 1's editor allows you to change that date field.
** The dates, as mentioned earlier, should be in ascending order.
** Please see [[amending dayfile]] page for more information on dates
** Both Cumulus 1 and MX may get confused if you restart the software close to rollover time, and in that confused state they may create a second line with same date as a date already in the file.
** If you regularly restart Cumulus close to rollover time, then a whole sequence of dates can be repeated either as a block or as pairs.
* The remaining fields are all either numerical values, or a time paired with (except for first wind field) preceding numerical value.
** Cumulus 1 actually enforces this pairing (i.e. it validates that a time is present where it is needed). Cumulus MX only validates that each field is of correct type, it does not recognise any relationships between fields.
*The alphabetic column identifiers used by many spreadsheet editors are shown in the table
** IMPORTANT: If you do use a spreadsheet editor, do ensure '''all columns are set to "text" format''',
** Note that you will corrupt this file if you let your spreadsheet recognise content as dates or time, or let it change the number of decimal places.
* The type of field is shown in the table:
** Note you must not include a sign for an unsigned field,
** Note you can not specify a decimal comma/point in an integer field,
** Note all fields of type time must use 5 character "HH:mm" format, although Cumulus 1 will accept other separator characters where ":" shown.
* The field description is shown, together with references to where that terminology is explained


== Table listing Fields ==

{| class="wikitable" border="1"
|-
!style="width:50px" | Field number
!style="width:50px" | Spreadsheet column
!style="width:200px" | Field type
!style="width:600px" | Description
|-
|0
|Colspan="4" style="background: pink;"|For internal MX purposes, the zero field identifies a field that holds the line number. It is not actually stored as a field in the log file, but precedes any line exchanged via an application programming interface, and therefore is also included in an array representing all the fields in any log file line.

If you are processing this log file using a third party (or your own) script, that probably does not place the line number into any array, and your array elements will start at 0 for the field labelled 1 in this table, so putting all field numbers out by 1.
|-
|colspan="4" style="background:lightgray;"|Those fields included below have been in dayfile.txt from the start of Cumulus 1 (Version 1.0, the First release on 27th January 2004).
|-
|1
|A
|8 characters
|Date as ''2 figure day [separator] 2 figure month [separator] 2 figure year'' - the separator is that set in the windows system short date format (see [[setup]])
|-
|2
|B
|Unsigned number
|Highest wind [[Wind_measurement#Weather_Stations_and_Cumulus|gust]] speed
|-
|3
|C
|unsigned integer
|[[Wind_measurement#Wind_Direction | Bearing]] of highest wind gust
|-
|4
|D
|5 characters
|Time of highest wind gust
|-
|5
|E
|signed decimal
|Minimum [[Temperature_(and_humidity)_measurement#Cumulus_Calculated_Parameters | temperature]]
|-
|6
|F
|5 characters
|Time of minimum temperature
|-
|7
|G
|signed decimal
|Maximum temperature
|-
|Colspan="4" style="background: pink;"| Consistency Note: In some cases Minimum comes before Maximum, in other cases Maximum is before Mimum
|-
|8
|H
|5 characters
|Time of maximum temperature
|-
|9
|I
|Unsigned number
|Minimum [[Pressure_Measurement | sea level pressure]]
|-
|10
|J
|5 characters
|Time of minimum pressure
|-
|11
|K
|Unsigned number
|Maximum sea level pressure
|-
|12
|L
|5 characters
|Time of maximum pressure
|-
|13
|M
|unsigned number
|Maximum [[Rain_measurement#Rain_Rate | rainfall rate]]
|-
|14
|N
|5 characters
|Time of maximum rainfall rate
|-
|15
|O
|unsigned number
|Total rainfall for the day
|-
|colspan="4" style="background:lightblue;"|Above here represents the minimum length for every line, a count of 15 items
|-
|colspan="4" style="background:pink;"|[There is no record of which version added this next field. The Cumulus Support Forum, while it was hosted by Steve Loft, moved to new forum software (phpBBB3) on 2 Jun 2008, and started afresh without retaining any previous content. Therefore all announcements about the content of each build prior to version 1.7.9 were lost. All that can be deduced is that it was between versions 1.2.5 and 1.5.1 as these do not appear in the release history issued by Steve Loft. The first mention of it in the new forum was not until December 2008, but that was not about when it was released. A web tag for this variable was added in Build 978 of 1.9.1 beta, which was obviously long after it was first calculated.

Because of that, in "DataEditor.cs" (part of the source code that is compiled into CumulusMX.exe) this addition has "Extended for ???" as a comment]
|-
|16
|P
|signed decimal
|[[Average temperature]] for the day
|-
|colspan="4" style="background:lightgray;"|(Wind run was added from version 1.8.4)
|-
|17
|Q
|unsigned number
|Daily [[Windrun | wind run]]
|-
|colspan="4" style="background:lightgray;"|(The next pair of entries were added from version 1.8.9 build 907 (June 2010) as part of a total redesign of how dayfile.txt was implemented in Cumulus 1)
|-
|18
|R
|unsigned number
|Highest [[Wind_measurement#Weather_Stations_and_Cumulus|Average Wind Speed]]
|-
|19
|S
|5 characters
|Time of Highest Avg. Wind speed
|-
|colspan="4" style="background:lightgray;"|(The two pairs of humidity entries were added in October 2010, a v 1.9.0 beta, the exact build number is now lost)
|-
|20
|T
|unsigned integer
|Lowest [[Temperature_(and_humidity)_measurement | humidity]]
|-
|21
|U
|5 characters
|Time of lowest humidity
|-
|22
|V
|unsigned integer
|Highest humidity
|-
|23
|W
|5 characters
|Time of highest humidity
|-
|colspan="4" style="background:lightgray;"|(The next two entries were added from version 1.9.0)
|-
|24
|X
|(not documented)
|Total evapotranspiration (Only valid for Davis stations, shows zero otherwise)
|-
|25
|Y
|unsigned
|Total hours of sunshine (only valid if sunshine sensor connected)

'''Important if rollover time is 9 am or 10 am:''' Most fields in this file are updated taking information from [[today.ini]]. For a non-midnight rollover, then the Sunshine hours reported here is from 00:01 on the calendar date corresponding to the date in the first field of this file, to subsequent midnight, and that end time is 9 or 10 hours before when this file is updated. Meanwhile, the sunshine hours count has been reset and so the figure in today.ini is not what is wanted here. For that reason the sunshine hours reported here are taken from [[yesterday.ini]].
|-
|colspan="4" style="background:lightgray;"|(The next 16 entries were added from version 1.9.1 May 2011)
|-
|26
|Z
|signed decimal
|High [[Heat index]] (added to Cumulus in 1.7.11 only as spot value, not stored)
|-
|27
|AA
|5 characters
|Time of high heat index
|-
|28
|AB
|Signed decimal
|High [[Apparent temperature]]
|-
|29
|AC
|5 characters
|Time of high apparent temperature
|-
|30
|AD
|signed decimal
|Low apparent temperature
|-
|31
|AE
|5 characters
|Time of low apparent temperature
|-
|32
|AF
|unsigned number
|High hourly rain
|-
|33
|AG
|5 characters
|Time of high hourly rain
|-
|34
|AH)
|signed decimal
|Greatest [[wind chill]] (high wind speed, low temperature) (calculated since version 1.8.3 as spot value, not stored)
|-
|35
|AI
|5 characters
|Time of greatest wind chill
|-
|colspan="4" style="background:lightgray;"|(The next two pairs for dew point were added in version 1.9.2 beta build)
|-
|36
|AJ
|signed decimal
|High [[Temperature_(and_humidity)_measurement#Cumulus_Calculated_Parameters | dew point]]
|-
|37
|AK
|5 characters
|Time of high dew point
|-
|38
|AL
|signed decimal
|Low dew point
|-
|39
|AM)
|5 characters
|Time of low dew point
|-
|colspan="4" style="background:lightgray;"|(The next three entries were added in version 1.9.2 Build 1004)
|-
|40
|AN
|unsigned integer
|Today's dominant/average wind direction
|-
|41
|AO
|unsigned decimal
|[[Heat/cold degree days and Chill hours | Heating degree days]]
|-
|42
|AP
|unsigned decimal
|[[Heat/cold degree days and Chill hours | Cooling degree days]]
|-
|colspan="4" style="background:lightgray;"|The next two pairs were added in legacy version 1.9.3 build 1036 (these only show valid values if appropriate sensors exist).

Fields listed up to those following here applied to the final legacy Cumulus 1.9.4 and formed the basis for early releases of Cumulus MX.
|-
|43
|AQ
|unsigned decimal
|High solar radiation
|-
|44
|AR
|5 characters
|Time of high solar radiation
|-
|45
|AS
|unsigned decimal
|High UV Index
|-
|46
|AT
|5 characters
|Time of high UV Index
|-
|colspan="4" style="background:lightgray;"|The next two pairs were added in MX release 3.6.0, 2 more derived values and their times
|-
|47
|AU
|signed decimal
|High [[Feels Like]] temperature
|-
|48
|AV
|5 characters
|Time of high feels like temperature
|-
|49
|AW
|signed decimal
|Low Feels Like temperature
|-
|50
|AX
|5 characters
|Time of low feels like temperature
|-
|colspan="4" style="background:lightgray;"|The next two pairs were added in release 3.6.12

*Version 3.6.12 (build 3088) was an emergency release to cure serious problems in previous build 3087. It added the following 4 fields (2 values and their times).
**The 4 extra fields are left empty in this release, although you can add values and time-stamps using the dayfile editor.
*From release 3.7.0 the first 2 of these 4 fields are populated, and the last 2 are removed, so I have labelled them as error.
|-
|51
|AY
|signed decimal
|High Canadian Humidity Index or [[Humidex]]
|-
|52
|AZ
|5 characters
| style="background:pink;"|Time of high Humidex

'''Bug for releases 3.13.0 to 3.14.2 inclusive''': The major code rewrite for release 3.13.0 replaced the previous code for the processing for all Cumulus files, the new code incorrectly stored ''Time of high feels like temperature'' in this field for all these releases! Corrected in minor code rewrite for 3.14.3 - b3163 25 Jan 2022 (not released to public until 3.15.0 - b3169 Released 31 Jan 2022)
|-
|colspan="4" style="background:lightblue;"|Just confirming that the next 2 fields were included by mistake in an emergency release (3.6.12), and are not included in any other version, so have labelled them as error.
|-
| 53 ('''error''')
| BA
| signed decimal
| Labelled as Low Humidex, but not used, (appear in 3.6.12, but no other release)
|-
| 54 ('''error''')
| BB
| 5 characters
| Labelled as Time of low Humidex, but not used, (appear in 3.6.12, but no other release)
|-
|colspan="4" style="background:lightgray;"|The next value was added in release 3.12.0
|-
| 53 (new)
| BA
| unsigned decimal
| [[Heat/cold_degree_days_and_Chill_hours#Chill_Hours_and.2For_Air_Frost|Cumulative Chill Hours]] since start of season
|-
|colspan="4" style="background:lightgray;"|The next value and time fields were added in release 3.20.0
|-
| 54
| BB
| unsigned decimal
| Highest rainfall total in (an approximate, as it depends upon timing of earlier entries in [[Recent history]]) 24 hour period ending in [[Meteorological day]]
|-
| 55
| BC
| 5 characters
| Time when (approximate) 24 hour period for rainfall total above ends
|}


==Example of the file==
==Example of the file==


An extract of a few lines of the dayfile.txt
An extract of a few lines of a dayfile.txt


<pre>
<pre>
Line 140: Line 515:
07/08/11,17.7,342,13:24,12.9,05:47,24.1,14:53,1013.92,19:49,1016.43,09:36,0.0,00:00,0.0,18.4,19.1,6.3,14:06,48,12:45,89,05:36,3.30,9.0,24.1,14:53,24.6,15:48,13.3,05:47,0.0,00:00,12.9,05:47,14.6,15:52,10.7,11:33,11,1.6,1.7
07/08/11,17.7,342,13:24,12.9,05:47,24.1,14:53,1013.92,19:49,1016.43,09:36,0.0,00:00,0.0,18.4,19.1,6.3,14:06,48,12:45,89,05:36,3.30,9.0,24.1,14:53,24.6,15:48,13.3,05:47,0.0,00:00,12.9,05:47,14.6,15:52,10.7,11:33,11,1.6,1.7
</pre>
</pre>

[[Category:Log Files]]

Latest revision as of 07:14, 27 September 2022

Cumulus Version MX SpecificCumulus Version 1 SpecificThis Wiki page applies to both Cumulus flavours.

As part of a redevelopment of Wiki, this page has been simplified, by moving some content to new pages. Old links in the support forum, that were to content no longer on this page, will bring you here.

Content previously on this page has been moved as follows:

The content that remains on this page is summarised by the table of contents that follows.

About this file

  • This Wiki page describes one of the files not included in any release download.
  • This daily summary file (Steve Loft shortened that to "day" plus "file") uses a ".txt" extension, and is essentially a plain text file in CSV format.
    • CSV stands for "Comma Separated Values", but in the Cumulus context the field separator can be other characters including ";" or "|"
  • The file is created in data sub-folder of your Cumulus installation when Cumulus needs to store its first line in this file.
  • Cumulus MX reads the whole of this file into an internal array (stored in RAM) each time you restart the software,
    • Please see here for implications
    • Therefore MX users who move to a different location should archive the old "dayfile.txt", to avoid any discontinuities in any graphs plotted from active file


(speciallog.txt is another log file that contains all dates in a single file, as do all the .ini files).


How Cumulus Creates and Updates this file

  • Cumulus reads values supplied by your weather station, (either directly while Cumulus running, or for some weather station types can read historic data during catch-up on restarting Cumulus)
  • Cumulus converts them to the units you prefer,
  • Cumulus applies any calibration (multiplier and offset) you have set,
  • For a sub-set of those readings (perhaps those every minute if readings are collected every 10 seconds), the spot values of source items like temperature, humidity, wind speed, can be used in calculations of derived items like "wind chill", "dewpoint" and "feel-like" temperature.
  • Cumulus then sees if the resulting soource, or derived, value implies any extreme records file needs to be updated
    • Daily extremes are held in today.ini and that is main source used when a new line is added to "dayfile.txt"


Why this file should be backed up

  • This file contains daily extremes, the accuracy of those daily extremes depends on the interval between the spot readings that are used as explained above.
  • If the file is corrupted, and not regenerated from a back-up, the only source of spot readings is the MMMyylog.txt files, and their interval might be only every half an hour (it has to be an exact fraction of an hour).
  • As explained here minima and maxima between such logging intervals are not recorded by Cumulus software
  • Thus it is worth backing up this file, to another device than that running Cumulus, on a regular basis, probably a few times a week, to ensure this precious data is not lost if your device running Cumulus has a malfunction (or is damaged), or an electrical blip (or mistake by you) causes corruption to the original file,

Cumulus does periodically copy this file within the installation, but the copies are only kept for a limited time, and are on the same physical storage device, and so your main file is corrupted you might not be able to access the Cumulus back up or might not be able to go far back enough to find a file that has not been corrupted:

  • The file is backed up when MX is restarted into a date/time stamped sub-folder of the backup folder
  • The file is also backed up (to a date/time stamped sub-folder within daily sub-folder of that backup sub-folder) during the end of day process, but (depending on the release you are running) the back-up copy may, or may not, include a line for the previous day (the line that is appended in the same end of day)

Retention of these back ups:

  • Badge vMx.png MX only keeps the last 9 of the date/time stamped sub-folders.
  • Badge v1.png Legacy Cumulus 1 only keeps up to 8 of the date/time stamped sub-folders.

Specific issues for MX

WARNING: It is important to note that some releases of MX are very fussy about consistency in all lines of dayfile.txt. Earlier releases tended to have better compatibility with the legacy software. Subsequent releases expected every line to be expressed exactly as specified in the locale. MX in its latest release is trying to cope better with inconsistent date separators.

Date field: Cumulus 1 (C1) did not care what character (or characters) separated the day, month, and year elements of the date field. MX insists that the same character (or characters), as defined in the locale, is used for all lines in file.

Real number fields: MX uses the locale to decide what character (decimal comma or decimal point) separates integer and decimal parts of numbers. Every line of the file must be consistent in use of integer/decimal separator. C1 used the Region settings in Microsoft's Control Panel to determine how to store (and output) numbers for you, but (except if list separation character was comma) was fairly tolerant when reading old data in files. At the time of writing this, it was proposed the next major release will force this file to use decimal points (full stops not commas) regardless of locale. This proposal may or may not happen, the point is that information here might be incorrect for the release that you are using.

Time-stamp fields: MX insists on HH:mm format being consistently used in every line of file, C1 did not care what (non-space, non-field separator) symbol separated the minutes from the hours.

Number of fields: The number of fields in the file increases in various versions as shown in #List_of_fields.

  • C1 will accept (as did Cumulus 2) any line with 15 to 45 fields in it. This is because the earliest version only stored 15 fields, as C1 was developed fields were added (as shown in field list) until there were 45 fields.
  • Each release of MX expects a particular number of fields in each line of file; MX has added fields as the software has developed, and it even (as shown in field list) inadvertently added 2 fields later removed. The difference is that MX (for some functionality from release 3.4.5, for all functionality from release 3.9.5) reads the whole file into an internal (RAM held) array with a fixed number of elements, therefore every line ends up with same number of fields when written back into file.
    • If you have some lines in your file that were created by an earlier release of Cumulus, and so have less than whatever is the current number of fields for the release you are using, there is a utility to run that will create a new dayfile.txt with all fields populated, please see Calculate Missing Values page. Please ensure you use the right version of the "Create Missing" utility mentioned on that page as it also get upgraded when fields are added, and it uses various software libraries contained within .dll files specific to a particular CumulusMX.exe release.

How to view or edit this file

The detailed information has been moved to viewing/editing dayfile.txt page.

An editor has been included within recent Cumulus releases of each flavour:

  • Badge vMx.png Available from release 3.4.5 (13 Mar 2020): In the interface go to Data logs menu and select Dayfile
  • Badge v1.png Available from version 1.9.2 (5th October 2011) to final legacy release: On Main Screen from Edit menu select Dayfile.txt
    • Note for obsolete version 1.9.0 to 1.9.3: There is a bug in these versions in that 'Create missing' inserts 'heating and cooling degree day' values the wrong way round.
    • Note for obsolete version 1.9.3 only: Create missing might in some cases be affected by a bug in 1.9.3 that can cause lines to be stored in incorrect date order (dayfile.txt uses dd.mm.yy, dd/mm/yy or dd-mm-yy, for its date field; and all lines should be in ascending chronological order)
    • There are no known bugs for dayfile.txt handling in version 1.9.4 builds 1086 to 1101. Build 1099 is the standard stable final release of Cumulus 1 for most weather station types, 1100 and 1101 are for specific weather station types.

Please note that the editor in Cumulus 1 allows you to change the date, as well as all the other fields, although the lines must be kept in ascending date order to avoid errors when subsequently reading the file.

The MX editor does not let you change the date, you can only change other fields or delete an entire line, so you have no control over the order of the lines in the file.


Reading the file

See Daily Summary page for a full discussion of ways, external to Cumulus, to read this file.

Apart from the viewing/editing options just described, Cumulus software reads this daily summary file in vaCumulus 1 does not actually number lines, however it does count lines as it reads them, so if there is an error when it reads the file, the original Cumulus will report the line number (numbering from 1) where it first found an error (line numbering uniquely identifies the line, even if a date is duplicated, or a line feed has been deleted so two lines are merged).rious other circumstances depending on the release you are running.

  • Badge v1.png The legacy software only reads the file when the Cumulus user makes a specific request, in normal operation the existing content is ignored:
  • Badge vMx.png As already mentioned, MX reads the entire dayfile.txt file when it is first started into an internally held array. That internal copy was introduced in release 3.9.2 - b3097 (7 Dec 2020), it was needed to drive the historic charts functionality; both in the interface, and the example included Historic Charts web page.
    • From release 3.20.0 - b3200 (21 Aug 2022) there is a This Period Highs and Lows web page (accessed from Records menu) which is similar to the screens for viewing data for various periods except that the extremes it shows match those tracked in .Ini files.
    • From release 3.20.0 - b3200 (21 Aug 2022) there is an option to Reload dayfile in a Utils menu, this updates the internal held array by reading the file again; essential if an edit has been made to the file.

Line numbering and Error messages

Cumulus 1 does not actually number lines, however it does count lines as it reads them, so if there is an error when it reads the file, the original Cumulus will report the line number (numbering from 1) where it first found an error.

Cumulus MX stores the contents of the file in an internal two dimensional array. The outer dimension is identified by numbering (from zero) what were lines in the file. The inner dimension has that line number as element zero, and the fields taken from file are therefore numbered from one.

Obviously, line numbering uniquely identifies the line, even if a date is duplicated, or a line feed has been deleted so two lines are merged in the file. This is why you will see line numbers quoted in any error messages related to this file.

Some of the editors you may use to view/edit the file may number the lines (in some cases always, in others as an option). If you have seen an error message, then to correct the file you need to use a tool that does number the lines in order to find where the correction is needed. Error messages report just the first error found, so check subsequent lines in case they have same error.

List of fields in dayfile.txt

For your installed build please see dayfileheader.txt. This file identifies all the fields in each line of the dayfile.txt file in the release you are running.

That file has changed location from release 3.20.0 - b3200 (21 Aug 2022), it is now in data folder, for Cumulus 1 and all earlier MX releases it was in same directory as the Cumulus executable.

As explained earlier, the number of fields in a line has (with one exception when fields were added in error) increased as the Cumulus software has been developed. The table below therefore groups the fields under labels that indicate which version/release introduced them.

Field numbering

The table below was first created when the only flavour of Cumulus software available was what we now call the legacy Cumulus 1. Back then the fields were numbered starting from zero. This reflected the way fields were identified when processed as elements of an single-dimension array variable representing a line.

The old numbering from zero had two advantages:

  1. It stressed that the date field was different to the rest, all other fields were either values or time-stamps
  2. Numbering starting from zero is consistent with standard indexing used for arrays in programming languages (like JavaScript), so the number shown was the number to quote in any scripts where a Cumulus 1 line was converted to an array, and you needed to address a single field.

Please note the list of fields has been rewritten especially for MX. As part of the rewrite, the fields have been renumbered, in some forum posts you might see references to old numbering, in others to new numbering. As explained above the fields are now numbered starting from 1 to fit in with an internal array created when the log file is read, the processing code adds a line number in front of the date field on each array 'line' it holds.

Information shown in the table

  • The date is supposed to be a unique identifier, the same date should not be repeated in another line, however Cumulus 1's editor allows you to change that date field.
    • The dates, as mentioned earlier, should be in ascending order.
    • Please see amending dayfile page for more information on dates
    • Both Cumulus 1 and MX may get confused if you restart the software close to rollover time, and in that confused state they may create a second line with same date as a date already in the file.
    • If you regularly restart Cumulus close to rollover time, then a whole sequence of dates can be repeated either as a block or as pairs.
  • The remaining fields are all either numerical values, or a time paired with (except for first wind field) preceding numerical value.
    • Cumulus 1 actually enforces this pairing (i.e. it validates that a time is present where it is needed). Cumulus MX only validates that each field is of correct type, it does not recognise any relationships between fields.
  • The alphabetic column identifiers used by many spreadsheet editors are shown in the table
    • IMPORTANT: If you do use a spreadsheet editor, do ensure all columns are set to "text" format,
    • Note that you will corrupt this file if you let your spreadsheet recognise content as dates or time, or let it change the number of decimal places.
  • The type of field is shown in the table:
    • Note you must not include a sign for an unsigned field,
    • Note you can not specify a decimal comma/point in an integer field,
    • Note all fields of type time must use 5 character "HH:mm" format, although Cumulus 1 will accept other separator characters where ":" shown.
  • The field description is shown, together with references to where that terminology is explained


Table listing Fields

Field number Spreadsheet column Field type Description
0 For internal MX purposes, the zero field identifies a field that holds the line number. It is not actually stored as a field in the log file, but precedes any line exchanged via an application programming interface, and therefore is also included in an array representing all the fields in any log file line.

If you are processing this log file using a third party (or your own) script, that probably does not place the line number into any array, and your array elements will start at 0 for the field labelled 1 in this table, so putting all field numbers out by 1.

Those fields included below have been in dayfile.txt from the start of Cumulus 1 (Version 1.0, the First release on 27th January 2004).
1 A 8 characters Date as 2 figure day [separator] 2 figure month [separator] 2 figure year - the separator is that set in the windows system short date format (see setup)
2 B Unsigned number Highest wind gust speed
3 C unsigned integer Bearing of highest wind gust
4 D 5 characters Time of highest wind gust
5 E signed decimal Minimum temperature
6 F 5 characters Time of minimum temperature
7 G signed decimal Maximum temperature
Consistency Note: In some cases Minimum comes before Maximum, in other cases Maximum is before Mimum
8 H 5 characters Time of maximum temperature
9 I Unsigned number Minimum sea level pressure
10 J 5 characters Time of minimum pressure
11 K Unsigned number Maximum sea level pressure
12 L 5 characters Time of maximum pressure
13 M unsigned number Maximum rainfall rate
14 N 5 characters Time of maximum rainfall rate
15 O unsigned number Total rainfall for the day
Above here represents the minimum length for every line, a count of 15 items
[There is no record of which version added this next field. The Cumulus Support Forum, while it was hosted by Steve Loft, moved to new forum software (phpBBB3) on 2 Jun 2008, and started afresh without retaining any previous content. Therefore all announcements about the content of each build prior to version 1.7.9 were lost. All that can be deduced is that it was between versions 1.2.5 and 1.5.1 as these do not appear in the release history issued by Steve Loft. The first mention of it in the new forum was not until December 2008, but that was not about when it was released. A web tag for this variable was added in Build 978 of 1.9.1 beta, which was obviously long after it was first calculated.

Because of that, in "DataEditor.cs" (part of the source code that is compiled into CumulusMX.exe) this addition has "Extended for ???" as a comment]

16 P signed decimal Average temperature for the day
(Wind run was added from version 1.8.4)
17 Q unsigned number Daily wind run
(The next pair of entries were added from version 1.8.9 build 907 (June 2010) as part of a total redesign of how dayfile.txt was implemented in Cumulus 1)
18 R unsigned number Highest Average Wind Speed
19 S 5 characters Time of Highest Avg. Wind speed
(The two pairs of humidity entries were added in October 2010, a v 1.9.0 beta, the exact build number is now lost)
20 T unsigned integer Lowest humidity
21 U 5 characters Time of lowest humidity
22 V unsigned integer Highest humidity
23 W 5 characters Time of highest humidity
(The next two entries were added from version 1.9.0)
24 X (not documented) Total evapotranspiration (Only valid for Davis stations, shows zero otherwise)
25 Y unsigned Total hours of sunshine (only valid if sunshine sensor connected)

Important if rollover time is 9 am or 10 am: Most fields in this file are updated taking information from today.ini. For a non-midnight rollover, then the Sunshine hours reported here is from 00:01 on the calendar date corresponding to the date in the first field of this file, to subsequent midnight, and that end time is 9 or 10 hours before when this file is updated. Meanwhile, the sunshine hours count has been reset and so the figure in today.ini is not what is wanted here. For that reason the sunshine hours reported here are taken from yesterday.ini.

(The next 16 entries were added from version 1.9.1 May 2011)
26 Z signed decimal High Heat index (added to Cumulus in 1.7.11 only as spot value, not stored)
27 AA 5 characters Time of high heat index
28 AB Signed decimal High Apparent temperature
29 AC 5 characters Time of high apparent temperature
30 AD signed decimal Low apparent temperature
31 AE 5 characters Time of low apparent temperature
32 AF unsigned number High hourly rain
33 AG 5 characters Time of high hourly rain
34 AH) signed decimal Greatest wind chill (high wind speed, low temperature) (calculated since version 1.8.3 as spot value, not stored)
35 AI 5 characters Time of greatest wind chill
(The next two pairs for dew point were added in version 1.9.2 beta build)
36 AJ signed decimal High dew point
37 AK 5 characters Time of high dew point
38 AL signed decimal Low dew point
39 AM) 5 characters Time of low dew point
(The next three entries were added in version 1.9.2 Build 1004)
40 AN unsigned integer Today's dominant/average wind direction
41 AO unsigned decimal Heating degree days
42 AP unsigned decimal Cooling degree days
The next two pairs were added in legacy version 1.9.3 build 1036 (these only show valid values if appropriate sensors exist).

Fields listed up to those following here applied to the final legacy Cumulus 1.9.4 and formed the basis for early releases of Cumulus MX.

43 AQ unsigned decimal High solar radiation
44 AR 5 characters Time of high solar radiation
45 AS unsigned decimal High UV Index
46 AT 5 characters Time of high UV Index
The next two pairs were added in MX release 3.6.0, 2 more derived values and their times
47 AU signed decimal High Feels Like temperature
48 AV 5 characters Time of high feels like temperature
49 AW signed decimal Low Feels Like temperature
50 AX 5 characters Time of low feels like temperature
The next two pairs were added in release 3.6.12
  • Version 3.6.12 (build 3088) was an emergency release to cure serious problems in previous build 3087. It added the following 4 fields (2 values and their times).
    • The 4 extra fields are left empty in this release, although you can add values and time-stamps using the dayfile editor.
  • From release 3.7.0 the first 2 of these 4 fields are populated, and the last 2 are removed, so I have labelled them as error.
51 AY signed decimal High Canadian Humidity Index or Humidex
52 AZ 5 characters Time of high Humidex

Bug for releases 3.13.0 to 3.14.2 inclusive: The major code rewrite for release 3.13.0 replaced the previous code for the processing for all Cumulus files, the new code incorrectly stored Time of high feels like temperature in this field for all these releases! Corrected in minor code rewrite for 3.14.3 - b3163 25 Jan 2022 (not released to public until 3.15.0 - b3169 Released 31 Jan 2022)

Just confirming that the next 2 fields were included by mistake in an emergency release (3.6.12), and are not included in any other version, so have labelled them as error.
53 (error) BA signed decimal Labelled as Low Humidex, but not used, (appear in 3.6.12, but no other release)
54 (error) BB 5 characters Labelled as Time of low Humidex, but not used, (appear in 3.6.12, but no other release)
The next value was added in release 3.12.0
53 (new) BA unsigned decimal Cumulative Chill Hours since start of season
The next value and time fields were added in release 3.20.0
54 BB unsigned decimal Highest rainfall total in (an approximate, as it depends upon timing of earlier entries in Recent history) 24 hour period ending in Meteorological day
55 BC 5 characters Time when (approximate) 24 hour period for rainfall total above ends

Example of the file

An extract of a few lines of a dayfile.txt

01/08/11,19.3,61,10:22,12.5,06:58,23.8,14:49,1014.26,20:46,1018.83,09:28,0.0,00:00,0.0,17.8,21.6,4.6,10:44,36,14:14,86,01:56,3.56,8.9,23.8,14:49,23.1,14:50,12.3,06:59,0.0,00:00,12.5,06:58,11.3,00:16,6.9,14:34,354,2.0,1.5

02/08/11,16.1,20,16:55,14.7,06:45,24.2,13:54,1013.79,19:13,1015.65,11:14,0.0,00:00,0.0,18.9,13.7,8.0,15:55,42,20:42,85,06:50,2.79,4.9,24.2,13:54,24.3,13:55,15.1,06:40,0.0,00:00,14.7,06:45,14.8,11:59,7.0,21:09,57,1.0,1.7

03/08/11,14.5,36,17:23,14.9,05:50,24.6,14:46,1012.70,18:44,1015.99,08:34,0.0,00:00,0.0,19.4,17.2,4.8,16:04,50,14:38,79,07:04,3.05,5.8,24.6,14:46,25.4,14:47,15.0,05:50,0.0,00:00,14.9,05:50,14.2,20:01,8.9,00:16,32,0.8,1.9

04/08/11,17.7,16,15:43,14.1,06:20,25.3,15:06,1013.08,18:42,1015.31,08:28,0.0,00:00,0.0,20.2,19.4,8.1,14:12,52,18:20,92,06:55,3.30,9.1,25.3,15:06,26.8,14:55,14.9,06:20,0.0,00:00,14.1,06:20,15.8,14:55,12.5,06:25,36,1.0,2.9

05/08/11,16.1,32,12:52,14.2,06:12,22.2,14:07,1013.89,00:01,1016.36,09:43,0.0,00:00,0.0,18.6,21.6,5.2,13:00,62,15:57,87,06:11,3.30,8.4,22.2,14:07,23.5,14:10,14.8,07:19,0.0,00:00,14.2,06:12,15.4,10:33,12.0,06:03,34,0.9,1.3

06/08/11,16.1,309,11:15,14.3,05:29,22.4,17:12,1014.46,20:02,1016.97,10:38,0.0,00:00,0.0,18.4,19.2,5.5,16:21,55,13:33,92,05:20,2.79,7.9,22.4,17:12,23.3,18:17,15.1,06:09,0.0,00:00,14.3,05:29,14.2,18:12,10.9,10:38,32,1.1,1.3

07/08/11,17.7,342,13:24,12.9,05:47,24.1,14:53,1013.92,19:49,1016.43,09:36,0.0,00:00,0.0,18.4,19.1,6.3,14:06,48,12:45,89,05:36,3.30,9.0,24.1,14:53,24.6,15:48,13.3,05:47,0.0,00:00,12.9,05:47,14.6,15:52,10.7,11:33,11,1.6,1.7