I live along the gulf coast of Alabama about 15 miles north of the beach so it gets hot here, not Texas hot but hot. I built the subcomponents of my RV in my house and when I was ready to begin final assembly I moved my Cessna 152 out to the ramp... (She was looking at me like "I've been living in this hanger for 10 years... What's going on???"). Incidentally, my 152 is now part of a flight school in Georgia.
After I had to start spending lots of time in this heat I had to come up with something. Here's what I did and as simple as it seems, it helped alot. Of course a fan ran all the time. I kept an ice chest full of ice and drinks and I also kept a spray bottle of water in there. I would get that chilled bottle of water out as often as needed and mist the ice cold spray on my head, face, neck, arms, chest etc. Sometimes wiping off with a towel and others just standing in the moving air. Along with drinking ice cold drinks it was the only thing that helped me make it through. The misting of cold water really helped. A few times I went so far as to hose my self off using the FBO's hose. Just using the spray bottle of water would leave me with a refreshed feeling along with a renewed energy and focus.