My app AirCompare is a smart home controller and makes system decisions based on local weather. Users have been seeing absurdly wrong (~10°F off) current temperatures, and of course that's a problem.
I've seen similar complaints on Reddit and one poster claims that Apple switched from whatever DarkSky was using (which seemed accurate) to a predictive model from IBM. Compare iOS15 to iOS16 and you may see a large discrepancy in the Weather app.
As a developer needing an accurate current temperature, I'm wondering if this is a temporary problem or whether we can expect this to continue going forward. If it's the latter, I'll need to find something more reliably accurate.