There is no way I would be caught dead wearing my Ascent pants in 90-100 degree weather.I like the Sitka ascent pants and the UA heat gear stuff. Also first lite is good too.
another thing to think about is boots. I have a pair of Vasque Breeze boots that, even though gortex, do breathe well and are not fully enclosed leather like other boots. This makes a difference and pack some Gold Bond Blue foot powder, life saver.