The 403 error doesn't come from your code but from Google. Google lets you know that you don't have permission to access the resource you were requesting, in this case the weather API, because it has been discontinued (403 technically stands for Forbidden, they could also have gone for 404 Not Found or 410 Gone).
For more information, read http://thenextweb.com/google/2012/08/28/did-google-just-quietly-kill-private-weather-api/
Other than that, your code is correct.