Try this
Set Location to "Always": On your iPhone, open Settings, go to Privacy & Security > Location Services, select Weather and Maps, and ensure access is set to Always rather than "While Using".
Toggling iCloud Sync Toggles: Go to your iPhone Settings > Apple ID > iCloud > Saved to iCloud (See All), turn off the toggles for Weather and Watch, wait a day, and turn them back on.
Check System Time: On your iPhone, verify that date and time settings are set to Automatic under Settings> General > Date & Time.
Force Restart: Hold down both the side button and the Digital Crown on your Apple Watch for 10 to 15 seconds until the Apple logo appears.