So I prefer working in Illustrator for layout bc I think that it's much easier to size and scale vector art. Also, it allowed me to focus on typography and layout before adding the fun imagery. Here's my process
Besides my three main screens, I wanted to deal with adding cities to the app. Here's the feedback loop for that.
I looked at a lot of weather apps and realized that so many of them gave WAYYY too much info. Basically, I figured that the main "at a glance info" could be distilled to location, current temps, snapshot of day and snapshot of 7 day. Secodary info was more granular i.e. temp over time or cutomizing location information.