the xml service provided by weather.com has changed slightly. They now choke if some fields such as the id and key are empty in the request URL, so I've nerfed them for now. I will put in a proper fix later, but this will work for now... you can get the module here.
Please note this module is for Drupal 5.x, I have not tested it with Drupal 6. jonfrancisskydiver has created a version for Drupal 6 with some nice additional features available here: http://drupal.org/project/weatherfacti so please use that if you are using Drupal 6.