For the last 14 months on iOS I’ve been using the Hello Weather app, unlocked. (It’s free, but you can unlock extra features for $8.99/yr.) Unlocked, you can switch between real-time weather and extended forecasts from four different sources: DarkSky, TheWeatherChannel, AccuWeather, and AerisWeather. I’ve regularly checked and compared predictions between them all and found that TheWeatherChannel has been just as accurate as DarkSky… yet they differ at any given moment in their results! So when I’m out I switch between them if I think there’s imminent precipitation.
I’m mostly staying indoors as a result of the pandemic so I haven’t needed to consult the app much in the last few weeks, but having bought the DarkSky app years ago, I get Notifications through it when it’s about to rain or about to stop raining; perhaps something’s changed recently but those Notifications have gotten really good.
According to Hello Weather’s blog they already have plans in place to replace DarkSky’s forecasts for the pro-unlock users once its API stops working.