Hello rajku and welcome to AF. Go to Settings > Location services > and make sure Use wireless networks and Location and Google search is on and see if that works.

Edit: Did you recently update your S3? I am actually having the same problem also, but if I come across a solution I'll be sure to share.

 

After turning off my device and turning it back on again it seems that the Acu weather update seems to be working now. I guess you could try that and see if you get the same result and I hope this helps.