I found the instructions on how to get the weather to work on WatchMaker faces when you have an iPhone.
I followed the instructions and now I have weather on my WatchMaker watch faces.
Even though I have an iPhone, this step under Android did the trick for me:
Go to WatchMaker WATCH app > double tap for Settings > Weather Source > From Watch
By Watchmaker WATCH app they mean the app on the watch and not the phone.
The default Yahoo Weather doesn't work with WatchMaker. Try choosing OpenWeatherMap under Settings, Weather, Weather Provider and see if that works. To use Wunderground you have to apply for a "key".