I just upgraded to OH 2.2 from 2.1 and added the Weather Underground binding. I got it setup and it was working just fine for a few hours and then it started failing. Checking in PaperUI, i see:
Status: OFFLINE - COMMUNICATION_ERROR An error occurred while running the Weather Underground request.
I set the debug log level for the binding to DEBUG and I see the url it uses to retrieve the data. If I copy and paste that url into my browser, I get back what looks like valid JSON containing weather info.