I'm using the latest version (1.5.5). Here's my city: http://www.weather.com/weather/today/S%E3o+Paulo+Brasil+BRXX0232
BTW, no city can be found at all. However, Cupertino seems to update with the correct info.
Try the beta copy posted in this thread
It's not perfect but it's often better than nothing.
Great, it worked! Thank you very much!