Ok, I'm a weather app junkie. Tried this one out,love it. But it won't update on mobile. Is this a "feature"? It complains about an API.. Running on a Lumia 640, 8.1. Still kinda new to the platform ..
Make sure the app is allowed to run in the background and has access to your location. You could uninstall and reinstall. I have this app on my 925 running 8.1 and there are no issues for me.