This is a site I found a couple of years ago that I have used many times in sizing my solar and wind systems. I have yet to find anyone else that has used it. A lot of you may have already found it but it may be new to some.
The site gives you access to mountains of detailed meteorological data for the entire planet. It is compiled by NASA and is summary data for areas approx 100x100km covering the entire globe. There is both solar and wind data as well as much more!
http://eosweb.larc.nasa.gov/sse/
Click on: 'Meteorology and Solar Energy'
Click on: 'Click on a desired map location'
Log on (new users just specify your password twice)
Select your location on the globe (click to recenter the image)
Zoom into view the individual data regions
Click <Submit for Data>
Select the data you wish to use (hold down <CTRL> for multiple selections)
Click <Submit> to view data.
Definitions and methodology are also available.
I hope that you find this useful!