There's more to this story... I have an iPhone 6 Plus (but will finally be upgrading to an iPhone 13 soon). It's stuck on iOS 12.5. I upgraded my iPad Pro to iPad OS 15 today, and suddenly the weather app on my iPhone 6 was 'factory reset' - all of my custom locations were gone! I was left with local, Cupertino, and New York. I've heard there were issues with the weather app on iOS 15, but for my iPad to affect my phone like that is very strange! Yes I'm sure the two are related, due to the very close timing (and never having an issue with the weather app on my iPhone for years). Anyone else have a similar experience?