Hi Lukas (and everyone else with this issue),
There was a bug discovered in firmware 2.1.4 that prevented the controller from correctly updating the weather data. This has been fixed and released in firmware 2.1.5. Please upgrade by following the guide here: https://opensprinkler.freshdesk.com/support/solutions/articles/5000381694-update-opensprinkler-firmware-with-downloads-
Thanks!