Yea – I think we might all have the same issue (or similar) going on. I made another thread too, because there are some differences.
In our case, the station we are now apparently using is far away. And I cannot confirm that OpenWeatherMap is even getting our data. They seem to have no way to verify that …
But the odd thing is the station that we are now using (?!) has had no rain at all recently, but we still have 0%.
Watering manually now these days … glad I caught it was 0% because we are about to get into the scorch season.