How to keep cool while (partially) dry camping all summer?

I find that if I swim before I go to bed and use a 12v fan that cools you down. The water is much cooler than your body temp. When scuba diving in the tropics even with 80 degree water after 3 dives the last one being a night dive you are quite chilled especially if you don't wear a wet suit even with 80-90 degree air temps.