I really miss the old weatherspark. It was extremely performant and also had by far the best/most useful UI visualizations of any weather app to date.

http://radar.oreilly.com/2011/09/weatherspark-weather-data-v...

https://kk.org/cooltools/weatherspark/

As I understand it, they didn't have the money to migrate from Flash to HTML5 and the current site is a shadow of it's former self.