This is one confusing part of probability. While there may be just a small chance of precipitation during any individual hour, there are many chances for precipitation throughout the entire day. Because there are more chances for precipitation, the probability for the whole day will be higher than for any single hour.
The more hours you wait, the more likely it will rain during at least one of them.
MWeather uses DarkSky up to iOS15. After that MWeather works with Apple Weather.
High / Low Temperature
Sunrise / Sunset Time
current Feels Like Temperature
Wind Speed and Direction
Amount of Rain
Waxing / Waning crescent
These little weather infos are called Complications and can be added by pressing hard (Force Touch) on the middle of your Apple Watch display and then tap on Customise. Then swipe to the right and choose the spot where you want the Complication to appear and scroll with the Digital Crown to MWeather. Press the Digital Crown to confirm.
Open the MWeather app on your iPhone. Now you should be able to dismiss the message by pressing OK. If not change the language or the units setting in the MWeather iOS app settings. Now the MWeather watchOS App should get the needed infos and the app begins to update the weather data. If that dosen't help restart your Apple Watch.
Open the saved locations list and tap „Edit“. On the right side of the „Edit“ button appears a lightbulp button (iOS "Light Appearance“ must be active). Tap it and you have activated the dark appearance.