It's New Year's Day, the temperature is 41°, and you're standing outside, shivering in swim trunks with a bunch of people known as the Boulder Polar Bear Club. A signal is given, and en masse you and your fellow bears start yelling and then leap into Colorado's Boulder Reservoir. Water temperature: 38º. James Boone
One of the more curious traditions brought to the West by immigrants of northern Europe, winter swimming events - commonly known as polar bear plunges - are growing in popularity. Some are loosely organized, while others include hot tubs, warming huts, music, and prizes. Nearly all encourage costumes and general zaniness. Not to mention a little faith in your cardiovascular system.
Top polar bear events in the West: