Pro-Lighting: Skies

Realistic Outdoor Lighting in an Instant
What if you had a tool that allowed you to instantly change your outdoor lighting to any time of the day, any weather, and be completely realistic?
The flexibility to choose any lighting style. The confidence to know that it will render. And the freedom to do what you do best: create art.
That's Pro-Lighting: Skies: the fastest, easiest and most realistic outdoor lighting available for Blender.
Finally, an all-in-one solution giving you:
A library of visually stunning real skies to choose from
An easy one-click click lighting solution
Accurate, realistic lighting for any outdoor scene

http://www.blenderguru.com/product/pro-lighting-skies/