+1

I was wearing a dark gray helmet during the summer and it was hot. I stopped by a local bike shop and purchased a white Giro and could not believe how much cooler it was compared to the less expensive gray helmet. It's also possible that Giro makes a better helmet but in my opinion, the color had a lot do with temperature. It's the reason people were white colors and not black in 100 degree temperature.

However, I did purchase my first black one this winter, a Bern helmet. This will be for winter riding only and not summer.