The largest windmill farm I have ever seen is along I-10 just west of Palm Springs, CA. Every time I have been through this area it has been windy.
That's because I-10 cuts through San Gorgonio Pass el. 2,600 ft (790 m) at this point and all the wind funnels through this spot. The San Gorgonio Pass runs between the San Bernardino Mountains on the north and the San Jacinto Mountains to the south. Like the Cajon Pass to the northwest, it was also created by the San Andreas Fault.
Look at these photos and you can see the different types of windmills that have been put up through the years.
The San Gorgonio Pass provides the main link between the Los Angeles Basin and the Coachella Valley and points further east.
The pass itself is not as steep as the Cajon Pass or the Tejon Pass (the Grapevine), but it is still one of the deepest mountain passes in the 48 contiguous states, with the mountains to either side rising almost 9,000 ft (2,700 m) above the pass.
When I was driving motorhomes four years ago, I drove through all these passes but the San Gorgonio is the one I went through the most.