From Cumulus Wiki

Help with ‘Stable’ releases

Please read the announcement for the latest MX release in the forum before installing it.

We strongly advise updating to the latest version, if only for the fact that later versions offer more functionality, and may fix any bugs in an earlier release.

If you are upgrading from a previous version of Cumulus 1 or MX, please read all of the release notes (in the appropriate forum announcement threads) for the builds since the version you are upgrading from.

Note you may find that anti-virus software flag a new release of Cumulus as a ‘threat’, for a few days or weeks after a new version has been released, even though it does not actually contain a virus of any kind. This is due to a system they call ‘reputation’ where they automatically block any versions of software which have recently been released. You may want to consider complaining to the provider of your anti-virus software about this ridiculous system, or better still, use some better anti-virus software.

If you need any help with Cumulus MX, please first consult, in this Wiki, the Category:Cumulus MX page for pointers to articles that may help. If you cannot answer your questions from those links, then use the correct MX support forum to see if others have answers.

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.

Cumulus MX

Current Release

Note: Cumulus MX is strictly for non-commercial, non-government use only. It contains products produced by Highsoft which are not free for commercial and governmental use.

Latest build is...

NOTE: On Linux/RPi/macOS, Release v3.9.1 or later requires Mono version 5 or 6. Mono v4 is subject to random crashes.

  • There is also a pre-built disk image file for the Raspberry Pi that can be downloaded from here: rPi Cumulus MX 3.10.5
The instructions for using this image can be found here: Raspberry Pi Image

Developed from

Cumulus 3 (MX) software was developed as a beta with limited functionality by Steve Loft, who also developed Cumulus 2 (where he tested using the C# language, now used for MX) and the original Cumulus software (now known as legacy cumulus 1) which was created just for his use, and then developed over the next decade to include requirements suggested by thousands of users.

Steve Loft, the author of Cumulus/Cumulus MX has retired and will not be providing support, or updates, to Cumulus 1 or Cumulus MX software.

Steve's final beta MX

You can download below the final beta release and subsequent final source code as made available by Steve Loft as he handed the project over to "the community".

  • Cumulus MX v3.0.0 build 3043, 20-Jan-2017 Cumulus MX, a cross platform version of Cumulus which runs on Windows, Linux (including the Raspberry Pi) and Mac OS X (Steve Loft - final release).
  • Cumulus MX Source Code The original source code from Steve Loft. This version of the code is post b3043 as it includes some changes that Steve had made, but not yet released. Offered completely without support in the hope that it might be useful. The code is very badly structured due to the 'Frankenstein' way it was cobbled together from various places. Some of it is a machine translation of parts of Cumulus 1.

Other utilities

Utility for Fine Offset Stations

Weather Display Converter

This utility was provided by Steve to convert Weather Display log files to Cumulus format. It requires you manually recreate records etc using Cumulus 1. Please read the readme file in the zip.

There is a forum thread about this converter here.

WeatherLink Converter

This utility was provided by Steve to convert WeatherLink log files to Cumulus format. Please read the readme file in the zip.

There is a forum thread about this converter here.

Create Missing

A utility to create missing entries in your dayfile.txt. You may use this to add additional new fields that are missing from records created with old versions of Cumulus, or to create a whole new dayfile if you are starting afresh with monthly data imported from another program.

The v1.0.2 download dated 11 Mar 2021 is here.

More information can be found here.


A utility to export Cumulus MX monthly and dayfile logs to a MySQL database.

The v1.2.3 download dated 21 Mar 2021 is here.

More information can be found here.

Legacy releases

See this page.

Cumulus 1

The installer for Cumulus 1 is available here *Cumulus 1098 installer.

  • Cumulus 1.9.4 build 1099.2 patch Patched version of Cumulus.exe, allows date entries on NOAA reports and Snow Index up to the year 2030 (updated 28 Jan 2020). Note this is not the full installation version just a patched .exe.

Special Variants

  • Cumulus 1.9.4 build 1100 setup Use ONLY if you are an Instromet user, and your logger operates at 115200 baud, you should use build 1100
  • Cumulus 1.9.4 build 1101 setup Use ONLY if you are an Instromet user, and your logger operates at 19200 baud, you should use build 1101
  • NOTE: These Cumulus 1.9.4 variants will not have any updates in the future. In 2020, some of the menu items with year choices will not display years beyond 2020. This will happen on manual generation of NOAA-style reports. The NOAA reports should continue to be automatically generated, but the capability to create them on-demand will only work through 2020. It is STRONGLY RECOMMENDED that users of Cumulus 1.9.4 and 1.9.4 variants migrate to Cumulus MX, which has ongoing support by mcrossley.


Cumulus 2

The software for Cumulus 2 is no longer available.

User contributions

For files and add-on's contributed by Cumulus users see these Categories Category:3rd Party Apps, Category:AddOns, Category:WebTools, and (current) Category:User_Contributions.