I love the new app and the ability to utilize all the watch faces on my S3 and my LG sport. Love it. Only question is how do you make the weather and other information stuff on the face of the watch. Again LOVE THIS!! Home run. Would love to see multiple watch support in the app but other than that LOVE IT!!!
Creating current weather condition widget is pretty simple, as there is pre-made container available.
However creating a forecast widget is so far most challenging thing you can do. I tried to do that in this watch face: https://www.facer.io/watchface/XgFGmdkjw9
Challenge here is, that it does not behaves exactly as in documentation. Lot of weather codes does not match documented ones and you need to add a lot of new codes and try to apply them to weather icons (which you need to create yourself).
In a nutshell you need to create condition for each and every weather code and put each weather icon with conditional transparency x 5 days for a forecast. You will end up with like 100 conditionally hidden elements + from time to time you get some new weather code which you need to add, otherwise no icon will appear, as it does not match any current rule.
This is quite badly managed by Facer right now, I hope we will have some fix of this soon 
And just a quick example … insert img with your desired weather icon, in transparency put following code:
$#WFACI#=01?100:0$
Code 01 stands for “fair” conditions.
This you need to replicate multiple times for each weather condition and each 1-5 days beforehand.