Wunderground has lots of data available. They may have actually been part of this deal as they were owned by The Weather Channel.
http://www.wunderground.com/history/airport/KSFO/2015/10/28/...
http://www.wunderground.com/history/airport/KSFO/2015/10/28/...
Source: http://www.cnbc.com/2015/10/28/ibm-plans-to-acquire-the-weat...
api: http://www.wunderground.com/weather/api/d/docs
National weather service, http://weather.gov is my goto weather forecaster, but at the time I wrote the code, getting hourly data based on lat/long for several thousand locations (some outside the US) was problematic. and XML..