The unit of sensor.rain_lastsixhours cannot be converted to the unit of previously compiled statistics (None). Generation of long term statistics will be suppressed unless the unit changes back to None or a compatible unit.
In fact, I’m not at home right now, but maybe I’ll go over on Tuesday and pour something in from the watering can…
The only problem is that I’ll then mess up everything else: the lawnmower will stop mowing and the irrigation system won’t be switched on for a while although it’s about 30 degrees Celsius for some weeks now staying dry because it “rained” …