Polar bear swim
Usually not "swimming" per se, Williams' polar bears immerse themselves in bodies of water outdoors at all times of the year, especially in excruciating cold. It is a tradition and a kind of rite, from the walk across campus in the wee morning or dead of night, holding towels, all the way to shivering nakedness at the water's edge, thinking all the time about turning back. Those who persist are rewarded with an incredible adrenaline rush, an almost-magical feeling of warmth upon emerging from the frigid waters, and permanent bragging rights.
The toughest polar bears have been known to break holes in ice that had formed on the river in the dead of winter, so that they could then jump in. So you think you're hardcore?
 Getting to Polar Bear Swim
Outdoor bodies of water have a funny way of getting cold in the long Massachusetts winters. Therefore, a polar bear swim can happen anywhere there is a safe, relatively clean and perhaps relatively secluded body of water. However, it is safer to go in a group, and the Outing Club runs regular swims for anyone interested in participating. Their most common destination is the Green River. The Polar Bears currently meet on the Paresky steps at 10 PM on Tuesday nights.
Some say you achieve official polar bear status when you have immersed yourself outdoors at least once each month, on a regular basis -- no planning for warm weather! Going with the Outing Club provides you with a regular schedule, friends who will watch out for you, encourage you, and perhaps fetch your sandals if they go floating down the river.
 Surviving a Polar Bear Swim
Spring, summer, and fall polar bear swims tend to be fairly casual affairs, but when winter arrives and the temperature falls below freezing it's important to plan your dress carefully. Wear layers out to the site. Overdress. Have warm clothing for every part of your skin; don't neglect gloves, wool socks, and especially a full hat -- one that covers the ears. Avoid anything made from cotton; cotton dries slowly and is not warm when wet. Bring a sleeping pad to stand on if there is snow on the ground; you'll want to keep your toes dry and insulated as you undress.
As you remove your street clothes, arrange them with a thought to redressing quickly. Your hat should be the last thing to come off and the first thing you put on, then socks and gloves. Place all of these in safe, dry places, perhaps suspended from low branches.
When you get to the water, time your undressing so you are not standing in your skinnies for longer than you have to before immersing yourself. You will need to take off any clothing that gets wet afterwards or it will suck your body heat (while freezing into a cool shape). It is almost certainly best you don't wear clothing into the water.
When it is time, run into the water as deep as you can take it. Don't try to swim, and don't try to go in a little at a time, or you won't ever go in. Enjoy the thrill of being in the chill, and immediately run out and dry off very thoroughly before dressing.
 Song of the Polar Bears
On official WOC-lead polar bear swims, a little ditty is traditionally recited by the swimmers after they have undressed/changed into swimwear, and before they enter the water. Historically it has sometimes been sung to the tune of "Bingo" (B-I-N-G-O, and Bingo was his name-o), but in modern times it is more commonly chanted.
In, in, in we go
In through the ice and snow
Even when it's ten below
'cause we are polar bears.