I live in Texas where it can also get to over 110°, and I have never seen anyone do this. We've all done the open the door, jump in to start the car, crank the AC, roll down the windows too. You gotta exhaust that baked air inside. It's so bad you avoid touching the car with bare hands. But again, not once would I think wasting water on the car would be a good idea or even a good thing to do.