Good luck on finding low humidity in Houston.
Year's ago some bright eyed genius was going to put one of those cooling plates (like in those little 12 volt coolers that run 40 degrees below the ambient temperature) in the top of a helmet. The problem was that the integrity of the helmet was compromised affecting head protection.
The theory was similar to not wearing a hat on a cold day. The heat rising through your body like a chimney was cooled by the plate thereby making your body feel cooler. With the advances in technology and material, I wonder if it's time to re-visit this idea?