iPad OS 16

If you did delete it, you should be able to re-download it from the App Store: link-> https://apps.apple.com/us/app/weather/id1069513131

If it has an Open button there instead of a cloud icon, then it was not deleted. You may have moved it into the App Library. You can tap the App Library icon on the right side of the dock, and look for the Weather App there, then drag it back onto a Home Screen.

Apps can be removed from the home screen without being deleted. Go to the App Library (swipe left past your last home screen). From there you can touch and hold an app and slide it left back to the home screen.

Also note the Search window at the top of the App Library.

If it was deleted, see the following from Delete built-in Apple apps from the Home Screen on your iOS 14 or later or iPadOS device or Apple Watch - Apple Support

Restore a built-in app that you deleted

1. On your iOS or iPadOS device, go to the App Store.
2. Search for the app. Make sure that you use the exact name of the app.
3. Tap the Redownload button .
4. Wait for the app to restore, then open it from your Home Screen.