LD comfort works best in more arid climates, but will work in almost any heat, BUT you do have to be moving---stopping, poking along, etc, you can get pretty warm quickly. Look up posts by bubba1---lots of good information from him.
mesh gear will work, but is not optimal for REALLY hot weather. textile mc gear is best for really hot weather, but again, you do have to be moving.
also, when it is really hot, a full face/modular helmet with the ldc helmet liner is cooler than a 1/2 or 3/4 helmet (I've tested this!-after using my modular for quite some time, I decided to use my old 3/4 helmet one day---thought I was gonna have a heat stroke!)
I like the Olympia Air Glide III pants. They come with a separate windbreaker type liner that one can wear like a pair of pants with a belt. The liner can be worn either under or over the Air Glide pants or any other pants. I sometimes wear the liner over my Levi's or cargo pants