I've actually registered to ask this exact same question. Monday my weather widget was working properly, not necessarily accurate, but at least it showed the right location. But now, I'm apparently in neutral territory, my mobile thinks its in Switzerland of all places. I'm not, I'm in the Netherlands.
It had a slight tumble where my SIM got slightly dislodged, so I had to shut it off to re-insert the SIM card correctly. When I turned it back on, this problem arose.
I've tried to reset the app, remove and close, do a reboot. Even redo my SIM, just in case something's wrong with that to get the correct info, but nothing's working. GPS is turned off, but if I open Google maps it shows my location pretty accurately. GPS on doesn't make a difference, I'm still apparently stuck in the Swiss alps.
As default I don't have the GPS turned on, so that was never the problem in locating my position for the app, just a working wifi connection.
I'm really stumped by this.