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.
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Just tested it out, as you said one can add multiple locations but use the same location with multiple weather services, so thats nice.
What I don't like is that you need to swipe between the different locations to see their data instead of just having one page with the graphs one under another, but I guess that is personal preference.
Also there is just one widget that shows multiple locations and that only shows the whole day summary. If you add the hourly widget you cannot change location, it always uses the same one. But that seems like a simple thing to request from the dev, so I will do that.
Thanks again, closest to what I want!
Sounds like what I wanted, don't mind the workaround if it results in it working as I'd like, thanks!
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 !
Thanks. I am not from the US.