Originally Posted by jyossarian
They're hot. I have something similar, a Protec Ace Dig that I only use when it's way below freezing. A bike helmet w/ all the vent holes is still safe although it needs to be replaced if you're in an accident and the helmet takes a blow to protect your head.
It is a sad and very poorly advertised truth that some, if not all, styrofoams get pretty rigid when temps drop below 50 degrees F. I learned that when I was with a Federal Safety Agency and went digging thru some old Tank Corp files.