Since yesterday the xfce4-weather-plugin 0.7.4 only shows "No Data" and the tooltip shows "Cannot update weather data". It's the same as bug #5541. I found this thread on a Fedora mailing list: http://lists.fedoraproject.org/pipermail/devel/2011-November/159056.html There it's said that weather.com has closed its free API and charges for its new one. I don't know if this is true.
*** This bug has been marked as a duplicate of bug 8105 ***