I don't think it's the moisture so much, I think it's the cold temperature on the outside versus the warmer temperature inside the helmet. Still, it might be cold enough there.
broodmceto wrote:
I forget what it's called, but try a bike shop (motorcycle) and they have defoggers that you wipe on the inside that prevents fogging.
Rain-X (I think) makes some wipes like this. I wiped mine out at Adcon with it one time and it stayed fog-free the whole weekend. Try Wally world, they should carry them.