Sure, I was referring to the mediocre temperature forecasting of Apple Weather. It is also inexplicable that my wife and I will receive different forecasts on our iPhones while standing next to each other in our home.
I suspect this isn't the case for you since you've spent time thinking about it. But for some people, it might make sense depending on their privacy settings, which can deny fine-grained location information to apps.
Honestly, I'd never thought to check, since I assumed the first-party Weather app wouldn't have a location opt-out. But it turns out Apple gives all the normal options (all the time, only when app is open, detailed location) that they give for third-party apps. Good for them! But sadly, our settings are identical and the discrepancies (both short-term and long-term forecasts) persist.
Just to be granular and pedantic: if your settings are identical and you are both denying the app your detailed location, then it still could make sense since you'd both be placed into slightly different locations. I also assume that isn't the case but am just mentioning it.
Pedantry is no trouble; we both allow detailed location, so there's no excuse for different results! It would also be bizarre to show a different long-term forecast to two people that are 1-2 miles apart (esp. in the Bay Area, where weather is relatively stable).
