From Meteorologist Group:
Meteorologist is a full featured, free, and open source weather program for Mac OS X. This version of Meteorologist supports multiple cities, new version checking, and many more features. Meteorologist represents both the efforts of the developers and the helpful and insightful comments of those who use this program. The Meteorologist project is hosted by SourceForge. SourceForge is a community for open source developers to collaborate on their projects, keep track of bug and feature requests, and other really cool things.