Weather forecasts have gone to dogshit in the last 2 years. Even same-day forecasts can shift on a dime unpredictably. It’s at the point where I check 3 apps. Until this year, I never had a time where I woke up to 0% chance of rain and sunny, then looked outside to see rain. Not a sun shower. A rainy day hour-long downpour.
Supposing you're right that weather forecasts have gone to dogshit (I'm skeptical because your evidence is anecdotal), there may be reasons beside AI for that.