I agree with kingwood here. You jsut get used to the hot weather. It might be because i am a kid, but the hot hasn't gotten to me yet. I just try to wear slightly tight shirts, so that i don't have any more cloth on me then needed. a hat helps too.
I also plan to take a gallon of water to the field. (I drink water like a horse)
Edit: Left the r out of shirts...Oops