Don't know if it's what you thought about but there is Breezy Weather which allows setting a location in one of the supported service. This means that you can specify several times the same location with different providers and access them by swiping right/left or setup a widget for each. It's available through Obtainium or on IzzyOnDroid F-droid repository.

I use AF weather

https://github.com/Gitsaibot/AF-Weather-Widget

to put multiple widgets for different locations on the screen. Shows at a glance the next 24 hours.

Supports US and EU locations which is a plus.

They are all using the same data set it all comes from the US government assuming you are in the US so it does not matter what app you use it is sad the US government was sued when they tried to come out with their own app so people could get the info from the source !