From Cumulus Wiki

Cumulus MX

a cross platform version of Cumulus (M Crossley update) that runs on Microsoft Windows, all varieties of UNIX and Linux (including the Raspberry Pi Operating System), and Mac OS X.
NOTE: On Linux/RPi/macOS, Mono version 5, or 6, is needed for CreateMissing.Exe, ExportToMySQL.exe, and CumulusMX.exe. All of these relating to MX Release v3.9.1 or later.
Mono v4 is subject to random crashes.

Usage Restriction

Note: Cumulus MX is strictly for non-commercial, non-government use only.

Both the mandatory MX Interface, and the optional default web site, contains products produced by Highsoft which are not free for commercial and governmental use.

Help with ‘Stable’ MX releases

Please read the announcement for the latest MX release in the forum before installing it (to see what changes affect you, and what actions you may need to take).

If you need any help with Cumulus MX, please first consult, in this Wiki, What_to_do_when_I_have_a_problem_with_MX, or use the entry point of the Category:Cumulus MX page for pointers to other Wiki pages connected with MX 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.


We strongly advise upgrading to the latest version, if only for the fact that later versions offer more functionality, and may fix any bugs in an earlier release. Also the developer can more easily offer support if you are using the build he most recently released.

It is strongly recommended that you install all files (there are inter-dependencies) in the download for a new release of MX directly over your existing installation. There is an installer utility available to help with upgrading.

  • Important, please read all of the release notes (in the appropriate forum announcement threads) for the builds since the version you are upgrading from, especially noting when there are references to necessary once-off actions.
  • If you have never upgraded before, or you are currently running a fairly old release of MX, you are advised to read the Updating MX to new version page in this Wiki,
    • overwriting an existing installation will add any new files, but it won't remove obsolete files, and sometimes replacement files have different names to their predecessors
    • (a few builds will include one-off actions, e.g. rewriting Cumulus.ini or changes to columns in database tables, in these cases you need to upgrade in multiple steps, to ensure these special actions are done).
  • If you are upgrading from a previous version of the legacy Cumulus 1, then you might want to read Migrating from Cumulus 1 to MX page; and if you need more justification read Compare legacy Cumulus and MX page

Note by Steve Loft: 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 that 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.

Current Release

Latest build distribution download

Download Cumulus MX v3.14.1 build 3160, 21-December-2021

Raspberry Pi Image

Download Raspberry Pi Image for Cumulus MX 3.13.0
As at December 2020, the image includes Raspberry Pi. O. S. 10 "Buster" version of Linux.

  • This is a pre-built disk image file for your first installation onto a Raspberry Pi computer.
  • This contains all you need;
    1. the lite version of the Raspberry Pi operating system
      • (this excludes all the graphical user interface, so is designed for a "headless" operation),
    2. latest mono-complete
      • ('built on a model 3, there might be issues when used on a model in a different series),
    3. a MX installation (in "/opt/CumulusMX") at the release version advertised above,
    4. code to create a temporary RAM drive
      • (using the memory on the chip will reduce wear of input/output operations on micro-SD card)
    5. a set of symbolic links in CumulusMX/web folder so that the temporary files created by MX are physically stored on that RAM drive
      • (any temporary file content lost on reboot).
  • The instructions for using this image can be found here: Raspberry Pi Image
    • Please note, this image may not always contain latest MX release, but once you have installed a release of MX on your Raspberry Pi, upgrading is done using main software download link, as none of the other components in the image need to be upgraded (unless the release announcement states that the new release needs a specific version of Mono).

Source download

This code base is updated for all releases resulting from development by M Crossley.

Older releases

It is always possible that a new release introduces a bug, and you decide to regress to an earlier release.

Find link to earlier MX release distributions on Main Page.

(You can search using the history tab on this Wiki page to see which past builds were made available as Raspberry Pi images, as these are not created for all releases, but there is no way to tell if the old filenames can still be downloaded. Generally, it is easiest to download a different normal MX release distribution over whatever MX release was in the image you downloaded.)

Other utilities

By Mark Crossley

Create Missing

The CreateMissing.exe v1.2.0 download dated 05 December 2021 (works with release of MX 3.14.0 onwards) is here.

If you are using an earlier MX release, upgrade that, before using this utility.

This is a MX utility, by Mark Crossley, to populate any missing derived fields from the source values in your month by month (MMMyylog.txt), and to insert missing lines in daily summary (dayfile.txt).

More information by the author of the utility can be found here.

  • Learn when this utility might be useful, and when not, by reading the Calculate Missing Values page.
  • Check in the support forum for information about status of bugs in this utility, e.g. it was reported that there were problems concerning storing the line in dayfile.txt for the first of some months
  • For full information about solving problems with your dayfile.txt file read the amending daily summary file page.

Export To MySQL

A utility, by Mark Crossley, to export content of Cumulus MX month by month (MMMyylog.txt) and daily summary (dayfile.txt) to a MySQL, or Maria, database server.

The ExportToMySQL.exe v1.4.0 download dated 05 December 2021 (works with release of MX 3.14.0 onwards) is here.

If you are using an earlier MX release, upgrade that, before using this utility.

More information by the author of the utility can be found here.

This new utility replaces the "ExportMySQL.exe" (no "To" in that name) utility included by Steve Loft in his MX beta distributions. That is not compatible with any recent MX releases.

By Steve Loft

Utility for Fine Offset Stations

  • Set Logger Interval A utility by Steve Loft to adjust the internal logging interval on Fine Offset stations

Weather Display Converter

This utility was provided by Steve to convert Weather Display log files to Cumulus 1 format, download here.

Please read the readme file in the zip.

There is a forum thread about using this converter with the legacy Cumulus here.

At time of creating this Wiki page, the functionality offered by MX was limited, and this utility was not useful with MX.

Since then, MX has developed and has changed so much, so this utility can be used with MX, but will not support all fields used by MX. It is advised you use #Create Missing (see above) after using this utility to populate the other fields.

If you do find this utility does not work with MX, you may need to manually recreate records, etc. using Cumulus 1, and then Migrate all your files from Cumulus 1 to MX.

WeatherLink Converter

This utility was provided by Steve to convert WeatherLink log files to Cumulus format, download here.

Please read the readme file in the zip.

Third Party Contributions by other Cumulus Users

For files, and add-on's, contributed by Cumulus users, see these Categories:

  1. Category:3rd Party Apps - contributions for various devices,
  2. Category:AddOns - adding extra functionality,
  3. Category:WebTools - for your web server, and
  4. Category:User_Contributions - key contributions from the user community

Current MX Developed from

Cumulus 3 (MX) software was developed as a beta with limited functionality by Steve Loft.

  • Steve Loft previously developed Cumulus 2 (where he tested using the C# language, now used for MX)
  • Steve Loft created the original Cumulus software (now known as legacy cumulus 1) just for his use, before making it generally available, he then developed it over the next decade to include requirements suggested by thousands of users.
  • Steve Loft, the author of Cumulus/Cumulus MX has since fully retired, and stopped providing support, or updates, to Cumulus 1 or Cumulus MX software.

Steve's final beta MX

You can download below the final beta release as made available by Steve Loft, and also his subsequent final source code.

If you are able to understand his source code (linked below), and compare it to the latest source code (linked above), you can appreciate the transformation that has taken place in recent years.

  • Cumulus MX v3.0.0 beta 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).
  • subsequent updated Cumulus MX Source Code from Steve Loft. He made the following comments, as he handed the project over to "the community":
    • 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.

Legacy releases

See downloads page for full details.

Cumulus 1

The installer for the FINAL release of the legacy Cumulus 1 is available here:

  1. Cumulus 1099 installer Full set of files within an installer.
  2. Cumulus 1.9.4 build 1099.2 patch Patched version of one file (Cumulus.exe) to replace that file from above installer,
    • modifies the drop-down year selectors, (on "this period" screens, for NOAA reports, and for Snow Index).
    • The new year drop-down selectors will make it easier to choose date entries up to the year 2030 (updated 28 Jan 2020).
    • Note this is not the full installation package, just one file to replace the suite of files created by the installer, a patched .exe.
      • Without the patch, on the "this period" type screens you can still manually enter any year,but you have to over-type with the full year yourself.
    • Without the patch, there is no problem with automatic generation of NOAA reports, but you cannot regenerate them.

There are still many people using this legacy software (some using final release version, some using earlier builds), so there is still some support available.

However, during 2020 to 2021 there was an avalanche of people who used to use the legacy software swapping to MX. Be aware, the longer you wait before swapping, the more that MX will have developed away from the legacy, and potentially the more difficulty you might encounter with the migration of your data files.

Special Variants

It is STRONGLY RECOMMENDED that users of Cumulus 1.9.4 variants migrate to Cumulus MX, which has ongoing support by Mark Crossley. The baud rate can be selected within MX as a configuration setting.

  • 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.
  • The patch for Cumulus.exe, cannot be used with these variants
  • The menu items with year drop-down selectors will not display years beyond 2020.
    • For example, this will happen on manual generation of NOAA-style reports.
    • This does not affect any automatic generation of NOAA reports, but does prevent re-generation.

Legacy Resources

  • Cumulus installation guide Instructions for installing Cumulus 1
  • Cumulus readme.txt Please read this before installing or updating Cumulus
  • Cumulus help file The Cumulus 1 help file (this also gets installed when Cumulus is installed)
  • Cumulus Realtime An obsolete Silverlight application for displaying 2 extra dials showing real time wind data on the standard Cumulus (with temperature and rainfall in histogram style) gauges page for a web site (no longer developed or supported)
  • Cumulus help file in French The Cumulus 1 help file translated into French

Cumulus 2

The software for Cumulus 2 is no longer available.