@SimonUrbanek Thank you for having a look at it. My iOS app version is 39.3.3. My watch says version 39.030353.
(but I have seen it already happening 2 weeks ago when I started using Windy more frequently - don't know which app version, but I check for updates pretty much daily).
From around 0:13 local time in Switzerland - screenshot with the most recent available app on both iPhone and watch: