canklecat

I'm in Texas. Any road type helmet -- the skeletal types with lots of vents -- will do. Preferably a light color. I use a white Bell Solar. Cost a whole $20 from Nashbar.

I wear a bandana underneath. And I have long hair which probably helps with evaporation -- I rarely get sweat pouring into my eyes, which was a problem years ago when I was in the Navy and had shorter hair.

Occasionally on really hot days I'll squirt some water on my noggin and jersey. I usually slobber water onto my legs anyway just from drinking. Helps. Carry extra water so you have some for impromptu cooling. The Hotter'N Hell Hundred is supported so you won't run out of water.

I used to ride without a helmet because the old types with fewer and smaller vents were too hot, even in Southern California. But the vented helmets are so lightweight and comfortable I can't think of a reason not to wear one. Also it gives me another place to mount lights and my video camera, although the camera does add some noticeable weight. The lights weigh almost nothing.