To address the issue of the Weather app not working on your iPhone, consider the following troubleshooting steps:
Check Internet Connection: Ensure you have a stable Wi-Fi or cellular connection.
Force Quit and Relaunch: Swipe up from the bottom of the screen to the center, and hold until you can see the App Switcher. Then, swipe upward on the Weather app card to close it. After waiting a few moments, tap the Weather app icon to reopen it.
Location Permissions: Verify that Location Services are enabled (Settings > Privacy & Security > Location Services), and that the Weather app has access to your location (Settings > Weather > Location).
Background App Refresh: Make sure Background App Refresh is enabled for the Weather app (Settings > General > Background App Refresh).
Low Power Mode: Disable Low Power Mode if it's on (tap the yellow battery icon in Control Center or go to Settings > Battery).
Update iOS: Check for iOS updates (Settings > General > Software Update) and install if available.
Server Status: Visit Apple's Support page to check the system status of the Weather service.
If these steps do not solve the problem, you may wish to reinstall the Weather app by pressing and holding the app until the contextual menu appears, then tap Remove App followed by Delete App, and reinstall it from the App Store. If the issue persists, contact Apple Support for further assistance.