Hi dmatrix,
It looks as if something is corrupt - first download a fresh copy of WeatherCat:
http://data.trixology.com/downloads/WeatherCat.zipIf that's showing the same problem, delete WeatherCat's preferences file and then reboot the machine (on 10.9 if you don't reboot, the old settings will hang about in memory). Deleting the preferences file will reset everything back to factory defaults.
You can find the preferences file at ~/Library/Preferences/com.trixology.weathercat.plist (where ~ is your home directory).
You may find your Library folder is hidden and you can't find it in your home folder If it is, you can make it visible again via the following terminal command:
chflags nohidden ~/Library/
Another way to go to this folder is to hold down the Option key while clicking on the Go menu in the Finder and selecting the 'Library' menu item.