Castelli's Vizio (or whatever they are now) shorts are probably the best I've found in hot, humid weather (I have the Vizio.1, which looks like the Vizio Due). Unfortunately, the chamois sucks, IMHO. Pearl Izumi's Elite In-R-Cool shorts are a very close second. I might see if I can swing a pair of the Pros for science.

I used my RS shorts on a not-hot but humid ride. I didn't like them as much as the Pearl Izumis.