Because Apple acquired weather company Dark Sky in 2020, the iPhone’s Weather app has learned some new tricks in iOS 15. (Note that this feature is yet to come to the iPad.) Most obvious is the app's addition of weather maps that can show precipitation, temperature, and air quality. More subtle are the notifications that can alert you to incoming precipitation at your precise location. To turn them on in Weather, tap the location button in the lower-right corner of the screen, tap Turn On Notifications, and agree to the necessary location and notification permissions when prompted. (You can also do this later in Settings > Weather > Location and Settings > Weather > Notifications.) From then on, whenever Weather expects precipitation to start or stop at any of your preset locations, you’ll get an alert. Stay up-to-date for improvements to the system, and use this feature to help keep you aware of dangerous conditions!