Weather app

In my opinion, none.
In my opinion, they’re all too inaccurate. Depending on the weather service, the nearest weather station from which the service obtains its data may be several kilometer away.

For a use case like this, I would suggest a capacitive rain sensor.
There are a few that are compatible with Homey, such as those from BleBox, Homematic (HM-Sen-RD-O) or Somfy, but they’re usually pretty expensive, and in some cases you need additional hubs.
But it’s also possible to build your own sensor:

Sorry, topics are in German.