You have explained why this information isn't useful for you. That's fine—your self assessment seems reasonable. By all means, delete all weather apps from your phone!
However I think I've also explained why I find the information incredibly useful, for different reasons than you. It's an incredibly valuable service to me and most of my immediate peers.
When I neglect to check the weather in the morning, I do things like wear a long sleeved shirt that becomes overly hot in the middle of the day, because the weather had felt slightly chilly that morning. I work in an indoor office, but I go out to get lunch, and it's nice to not be overly hot or cold.
I will say that I find weather forecasts more useful in Spring and Fall than Summer or Winter. Right now, the answer to "what should I wear?" is almost always "thick clothes and a coat!" But then, there are also exceptions, and using the weather forecast to spot them is great.
(Actually, speaking of temperature, something I didn't mention—my apartment is always hot, so even with the window open, it's often hard to judge the current outdoor temperature without an app.)
Edit: Also, whatever your complexion: if the UV Index is 0, you don't need sunscreen. And if the UV Index is 12+, you absolutely should have sunscreen even if you're inside most of the day. It's worth checking!