Reddit mentions of Frogg Toggs Chilly Pad Evaporative, Cooling, Snap Towel

You're laughing but that's really about how much water you should be bringing per person, per day. Honestly I might bring some extra in case there are any trip-related fuckups on wasting/losing water.

Bring some shade (like an EZ-up) to chill underneath. Hats. Suncreen (and use it often). You don't want to get fuckin toasted while you're tripping.

Also cooling towels like these that you get wet every now and then can really help cool you down during the day.

http://www.amazon.com/Frogg-Toggs-Chilly-Cooling-Towel/dp/B0049RPBWW

Apart from air circulation at night, I recommend the following:

1. Good insulation during the day. Not just blinds, put tin foil up on your windows to keep the sun away.
   
   
2. Cool your body, not the rooms. You can cool your hands or your neck -- what you're really doing is cooling your blood, and hence your core. You can do this by yourself (take a break every 30 mins and soak your hands in a bucket of ice water for 2 minutes), or find a commercial product.

Have you considered getting a chilly pad?

I live without AC in 90+ degree weather (+ outrageous humidity) and this towel thingy has been reeeeeeeally helpful.

I know it is way too late for tonight but there are these amazing towel things that help you stay cool in the heat. They are called Chilly Pads. I used one when I was outside last week when it was around 100 and I swear by the thing. Pretty amazing find!