@Korina Hello. After the watchOS update to 9.0.2, it looks like your complication is ok, and shown information is the proper one. I will do more tests and let you know if there are any problems.
Currently, 1h forecast and other Premium features are not yet supported in the Apple Watch. But it's something we will be working on.
@mjmarks Hello, weather units are synchronised with your settings in the app if you have iCloud option turned on. If you do not have it on or simply want to change ti manually, you can do so in Windy Watch settings. Complete Watch guide is - https://community.windy.com/topic/19303/windy-apple-watch-complete-guide