The thing about weather sites is that they usually overwhelm users with information. 80%+ of the time, a user wants to know, will i need a coat or umbrella today? Or the general temperature.

Thankfully, the weather channel has cleaned up forecasts (was once a huge mess): http://www.weather.com/weather/tenday/37202

Love this site: http://www.thefuckingweather.com/

I hope google make this available in their api as an overlay, I think my users would love it.