Caporegime
Dark Sky seems to be the best app for weather, it flashes me notifications saying "Drizzle starting now" just as it starts raining. It did the same for snow once when I was in the office. Neither I nor my colleague had seen any snow forecast but a minute or so after it gave me the notification, it started snowing.
I believe Apple bought it recently so it'll probably be integrated into the iOS weather app at some point.
WTForecast is good for a giggle for about five minutes.
Yes, it goes offline at the end of 2022. Presumably iOS 16 will have its functionality.