You lose the majority of your body heat through your head. By packing a hat, you’ll ensure that you stave off the effects of the wind and cold that awaits you outside. Whether it’s with a ball cap, knit cap or an art installation that looks like the NBA championship trophy, cover up your head.
Clearly, helmets can double as hats. Good news for vikings, rock climbers, cyclists and really clumsy people.
Oh, and water polo players. http://www.flickr.com/photos/thesistersoberth/4606910912/