Here's some tips from my end of things. (I say this as someone who lives in a variation of hell -- but with more humidity.)
-- Drink something in addition to water. Get a sports drink, bring some bananas for after the ride, etc.
-- Tech fabrics are awesome. I just bought some knee-length Nike Pro compression shorts (similar to Under Armour) that were thinner than UA and the seams were less bulky, that helps me breather under my jean breeches. I also have a Nike Climacool t-shirt that breathes quite well. I'll probably pair that with a UA tank top underneath, and/or a well-breathing sports bra.
-- Light layers. As others have mentioned, it's good to get the sun off of you and then have something underneath to control moisture.
-- Wearing a helmet that allows air flow. This is one I'm trying to solve at the moment, as my old IRH allows no air what so ever, so I'm looking at some alternatives.
ahhh im so glad this thread came up!! I know its just now getting hot in alabama but my body must not be used to the heat and after I got of of my ride I almost fainted, followed by a vomiting spell
... worst day ever.
Tell me about it! I did the same thing about 3 weeks ago. The temperature hit 90 and I had a 2 p.m. Lesson. Wow. I was fine riding, but once I dismounted, things went quickly downhill. I had to have my trainer untack my horse and turn him out, because I was sitting on the floor, trying not to pass out.
The lesson I had yesterday wasn't quite as bad, but there was still some light headedness when I was done. So, my trainer and I are rescheduling my lessons for early in the morning until it cools off here ... in December. :sigh: