Some users are facing difficulties when initially seting up YWeather. Usually this is because the geolocation API is not able to locate you, because you are inside a building and you have low GPS signal, or in some rare scenarios because the API itself is running slow and doesn't retrieve the data on a timely manner.
Usually this is fixed by following these simple steps:
1. From the YWeather settings, set the "use GPS" option to NO
2. Manually enter your location.
3 Configure the language and all the rest of the settings at your convenience
After submitting, the watchface should recognize all your settings and work properly. In most of the cases you should be able to set the "use GPS" back to YES and refresh the data based on you current location (but if you don't travel too much, your phone's battery will appreciate you keep the manual location) but if that still don't work to you, that may be because your Pebble app cannot access to your location services. If so, please ensure your GPS is turned on and Pebble app has access to access it.
Also, some Android users are unintentionally blocking the access to the location services due some "Power Management" options some manufacturers are adding to their custom roms. This also happens to some Cyanogen users, which have something called "Black List". Please, ensure everything is properly configured to allow YWeather access your GPS data.
If after following those steps you are still unable to make it work properly, contact me and I will help you.