From Cumulus Wiki
Revision as of 08:13, 1 July 2021 by Sfws (talk | contribs) (Date Selection)

Final Cumulus 1 version

Cumulus 1 has now been described as Legacy Software, simply because it is no longer supported, and can no longer be updated.

If you want to run Cumulus 1.9.4, there is no reason why you should not. It is a stable release, and only one bug has been identified.

The single known bug is that the original Cumulus software uses the wrong memory location for pressure for Fine Offset models. These weather stations are also considered legacy ones. There is a workaround described at FAQ#Cumulus_doesn.E2.80.99t_show_the_same_pressure_as_my_Fine_Offset_console.

Download Instructions

Please refer to Setup page first, so you understand how the installation process works. A more detailed (but now out of date) guide can be downloaded from Cumulus basic installation guide.pdf.

This is a multi-stage process:

  1. First Download the Windows Installer Package, the CumulusSetup.exe file here.
  2. Choose a location where you will install the software on your Microsoft Windows device
    • It is best to install to a root of whatever drive has plenty of spare space, this might be where you are using for your working files or normal documents
  3. Now run the installer, so it creates a large number of files and folders,
    Cumulus folder structure.PNG
    • (make sure the files and folders are installed in right location)
    • As you run the installer, read the instructions it displays (see below) Install screen.JPG.
    • This read me text can also be downloaded from a link in the resources section below
  4. When the installer has completed, there is another download to do.
  5. Now download the patch available here.
  6. Take the file "Cumulus.exe" from the patch, and use it to replace the file "Cumulus.exe" from whichever of the three installer packages you used earlier
  7. All other files from the full release, must be retained after applying the patch. The patch does not change any of the compiled code, nor its functionality.
  8. Start running Cumulus as instructed on Setup page.

Special Cumulus 1 versions

If you are an Instromet user, and your logger operates at 115200 baud, you should use special build 1100 at special 1.9.4 build 1100.

If you are an Instromet user, and your logger operates at 19200 baud, you should use special build 1101 at special 1.9.4 build 1101.

The patch, available in download above, can be applied after installing either of these special versions, it changes the GUI to make the drop down list cover years 2020 to 2030. As mentioned above, the patch only replaces the .exe file, all other files from special versions are retained.

Additional guidance

If you need any help with Cumulus 1, see if your question is answered, in this Wiki, on the original Cumulus software's FAQ page. If you cannot find your answer on that page, then use the correct C1 support forum to see if others have answers.

Date Selection

  • You can type any year you like into selection boxes on view month, view year, view period, and view NOAA report.
  • As well as directly typing in a date including a year into the selection box, you can pick some dates from the drop down boxes that can select some years, and (where relevant) any month and any day within any month.
  • The Cumulus installer provided by Steve Loft creates a year drop-down selection that only contains years 2008 (Cumulus was "born" in 2003, but not available to public until 2008) to 2020 (Steve Loft last worked on this software in 2014 and 2020 seemed a long way into future).
  • The Mark Crossley patch does not edit the software, it simply edits one component that changes the year drop-down selection to contains the years 2020 to 2030, making it easier to select years in the current decade (at time of typing this) in the relevant screen box.

Cumulus Help

One of the attractions of the original Cumulus software is that the installer installs a detailed set of help screens, so that each screen has a button that you can click for assistance, and the Main Screen has a Help menu where you can look up more guidance, such as web tags. The 1.9.4 helpfile can also be downloaded (for viewing using Windows Help) from link in resources section below. At the time of typing, it can also be viewed at Cumulus Top Weather Sites. See below for a translation into French.


  • Cumulus installation guide Instructions for installing Cumulus 1
    • (this 1 June 2010 edition is now out of date,
      1. as it gives out of date Universal Resource locators, quoting Steve Loft's hostname for Wiki and support forum
      2. as it relates to Microsoft Windows Operating Systems that are no longer available)
  • Cumulus readme.txt Please read this before installing or updating Cumulus
  • The "Microsoft Windows Help format" text files:
  • Cumulus Realtime An obsolete Silverlight application for displaying real time Cumulus data on a web site (no longer developed or supported)

Earlier Versions

Steve Loft, as well as updating the support forum with announcements about his releases for Cumulus 1, maintained an abbreviated summary in changes.txt, find it at It covers releases back to version 1.0, the first release on 27 January 2004, although the documentation for a small range within that was lost.

For the way dayfile.txt changed between versions, see that link.

For the logs created each month, see the example lines below:

0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	
Date (dd/mm/yy)	Time	Temperature	Humidity	Dew point	Wind speed	Recent high gust	Average wind bearing	Rainfall rate	Rainfall so far	Sea level pressure	Rainfall counter	Inside temperature	Inside humidity	Current gust	Wind chill	Heat Index	UV Index	Solar Radiation	Evapotranspiration	Annual Evapotranspiration	Apparent temperature	Max Solar radiation	Hours of sunshine	Wind bearing	RG-11 rain today	rain since midnight	
30-09-10	21:00	15.3	94	14.3	20.2	35.6	358	10.8	46.8	991	73.5	25.8	60	28.1	14	15.3	0	0	(version 1.9.0)								
22/04/11	10:30	8.1	96	7.5	13	20	142	0	0	1013.28	215.2	20.2	53	11	4.8	8.1	0	216	0.08	171.88	3.3	673	0	(version 1.9.1)			
01/10/11	04:40	18	75	13.5	5	6.7	169	0	0	1021.4	885.3	24.4	61	5.6	18	18	0	0	0	0	17.5	0	0	158	(version 1.9.2)		
01/05/12	04:40	18	75	13.5	5	6.7	169	0	0	1021.4	885.3	24.4	61	5.6	18	18	0	0	0	0	17.5	0	0	158	0	(version 1.9.3)	
02/10/13	22:40	14.2	99	14.1	0	0.7	207	0	0.3	29.85	961.5	119.5	53	0.7	14.2	14.2	0	0	0	0	15.5	0	0	225	0	2.4	(version 1.9.4)

Note about this article

It appears there was a bit of conflict between Downloads page and Software page. The main page previously said "We've added download links for Cumulus V1 and Cumulus MX in the new Software/Downloads page " because of this. Since then the Main Page has been updated, the legacy Cumulus and Cumulus MX links are now in separate columns of the table, and the introductory text has been revised.

  1. When Steve Loft was about to retire from involvement with Cumulus, he wanted to close his web server.
    • His server ( had hosted the wiki, the support forum, and some of the downloads were at
    • The other downloads (used mostly for beta and special releases) were at which was also closed.
    • In October 2018, Ken True ("saratogaWX") offered to host the Wiki on his site.
    • The Cumulus 1 software files were downloaded from the links just mentioned, and then added to this "Downloads" page by Ken as part of the migration of the Wiki.
    • Ken True added links to the help file download and the Cumulus 1 special downloads for Instromet.
  2. On 31 October 2018, Ken True, downloaded the final Cumulus MX release made by Steve Loft (from his Support Forum post) and created a new Page called Software for this.
    • Subsequently he added the source zip that Steve Loft made available (the source included some changes not in that Steve Loft
  3. The next month (November 2018), Steve Loft sought a new host for the support forum, as next part of closing his web server.
    • When Niall Hosiene ("Freddie") took over hosting of the forum, Ken True updated the relevant Wiki pages here.
  4. On 7 December 2018, Mark Crossley decided to take on further development of Cumulus MX
    • Mark added copies of Steve Loft's MX-beta release, and the released MX source to Marks' Github repository he created for Cumulus MX.
    • As Mark has developed MX further, he has added to this Github repository, the release complied code, the supporting files, and therefore the source files
    • Mark maintains the links to the Github repository for the latest release on the Software page of this Wiki.
    • The early releases by Mark continued to be labelled "beta release", but soon Mark brought MX out of beta, so links were described as "current release"
  5. In March 2019, Niall Hosiene (Freddie) edited the new Software page to make it one destination for both the "primary product" (MX) and what he renamed "legacy software" (original Cumulus 1), in removing the original "Downloads" page, he overlooked that other pages in this Wiki were still linking to the original Downloads page.
    • He was so keen to promote MX, his downgrade of Cumulus 1 to legacy, created some confusion by hiding some links that were still applicable in a MX world below Cumulus 1.
    • Mark made some changes to Neil's design for the Software page in October 2019, but there was a subsequent rollback to the "Freddie" March 2019 design

In April 2020:

  1. this wiki page was resurrected so the links to it from elsewhere in this Wiki worked again
    • this resurrection has given the chance to make this page devoted to Cumulus 1, and so much simpler and more detailed again
  2. the Software page has been improved by Ken True, grouping some downloads in a resources section
    • David (Water01) made some further changes to the Software page re Weatherlink converter and Weather Display
    • the Software page legacy section is currently a prećis of the detail available on this page, as it does have links to Cumulus 1 and the patch.