Weather channel
The weather channel sometimes / often shows the wrong day. How can I refresh this?
iPhone 7, iOS 13
About the Weather app and icons on your iPhone and iPod touch - Apple Support
Other than doing this which comes from the link above I am not aware of any way to refresh.
The weather data used in the Weather app comes from The Weather Channel. If you have issues getting accurate weather information, tap the icon in the lower-left corner to go directly to the weather source.
I have experienced this also especially in the early morning hours...