Help with Weather API for project (underground weather API)

So the problem Im having is that no matter what variable i try to access with my success function it always returns undefined. I had to run the url through cross origin work around because there were problems with security when I tried to access without cross origin. Here is my API info
Any help with this would be awesome, on a side note try not to run this too many times since the queries are limited to 10 a minute I believe.