I’ve been using the default Apple Weather app since getting my iPhone earlier this year. It’s been fine but over the last few days it seems to be less accurate in general.
I’m in Ireland if that matters.
Edit: Updated the title to include iOS specifically
I look at the sky through my window. I never understood the need for weather apps.
As it turns out, you can't see the weather outside several hours into the future, nor can you see the weather in places where you happen to not be at that particular moment.
Knowing these can be quite useful, to be able to dress appropriately, for example.
I do the same when I’m at my desk working. Sometimes I need to check the forecast, which is when a weather app is useful (e.g planning what clothing I’ll need for a cycle that will be multiple hours).