I thin the watering percentage suck at 0% has been fixed. It was caused by a combination of 1) some weather stations are reporting invalid data for precipitation; 2) a bug in the weather script that didn’t handle the invalid data properly.
The firmware queues a weather request every hour, and updates watering percentage accordingly. The reason I say ‘queues’ is that if a program is currently running (i.e. program busy), it will NOT check weather immediately:
https://github.com/OpenSprinkler/OpenSprinkler-Firmware/blob/master/main.cpp#L663
but will wait till the program has finished and then check. This is done to avoid confusion if in the middle of a program run the watering percentage changes. If you would rather want it to update even if a program is running, you can simply remove the “|| os.status.program_busy” part in the condition above.