It was so hot on the day of the OKC meet a few years ago that it was almost unbearable. I had a can of Coca Cola in my car and when I got back to the hotel, the can had exploded and sticky gooness was all over my car. I would much prefer an early spring or late fall meet (or even late winter, as the 2010 Tulsa meet was in February). One advantage to not having meets in the middle of summer is the lack of pests (bugs, snakes, rabid mammals, etc) that get in the way of meets, especially when meets often include bridges which usually span bodies of water.