Originally Posted by meme
Getting a white color helmet would also help as it won't absorb as much sunlight than say black color helmets.
Actually, I think somebody did some controlled tests on this theory and found the difference in temperature at the inside of the helmet was negligible between dark and light colored helmets. I'll try to find the article and post if possible. As I recall, the conclusion was that the foam that absorbs impact also acts as an insulator against the solar radiation, regardless of shell color.