I get the same error even on a connected device (debug build).

Similar problem here. Seeing lots of reports on StackOverflow as well. Some people say it only works when building on a real device, but that has not been the case for me. WeatherKit is not working with Xcode on simulator nor on device. [ iOS 16.1, macOS 13.0.1, Xcode 14.1 ]

I'm getting the same JWT error making any request with WeatherKit from Xcode. This includes on a real device and in the simulator. Seeing lots of people reporting the same problem on StackOverflow as well. I'm running Xcode 14.1 on macOS 13.0.1 and my device is an iPhone 13 Pro with iOS 16.1