I use the free Accuweather app (it does contain unobtrusive ads at the bottom). I don’t remember if it came with my phone or if I downloaded it.
Specifically, I like the radar, the allergy forecast, daily and hourly predictions. It has generally been spot on with the rain predictions here in socal, even to the hour. It has a widget feature, too. You may also store ~10 other locations, which is fun for upcoming travels. It also gives adverse weather alerts.
I believe you can upgrade to get more than 14 days and possibly no ads, but I’m fine with the free edition.
ETA: Android version
