Skaters in bright blue swim trunks, fuchsia tutus and cargo pants — and little else — cavorted on the ice despite 51-degree temperatures at the annual Polar Bear Skate in San Francisco’s Union Square on New Year’s Day.

The competitors donned their scant apparel and pirouetted, twirled and whirled at the Safeway Holiday Ice Rink, vying for prizes based on theme, originality and overall appearance. The uniquely Bay Area competition, sponsored by Safeway, is a takeoff on Polar Bear plunges and encourages skaters to compete in beachwear.

Natalie Renier-Bertolucci skates around at the Union Square holiday ice rink during the Polar Bear Skate. (Harika Maddala/Bay City News)

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One might think that this year’s unusually cold weather would deter even the most determined eccentric (or exhibitionist) from competing. But Bay Area residents displayed their courage, not to mention their bodies, without a trace of hesitation Saturday afternoon.

Joe Houston of San Francisco, the wearer of the aforementioned blue swim trunks, bested eight other contestants for first prize: Two tickets to the ice rink valid until Jan. 17; $100 Visa and Macy’s gift cards; and handmade vegan truffles from Petaluma-based Sjaak’s Organic Chocolates.

Joe Houston makes snow angels after winning the Polar Bear Skate contest at Union Square holiday ice rink. (Harika Maddala/Bay City News)

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It wouldn’t be accurate to say Houston skated easily to victory, either literally or figuratively, given the low temperature. While some of the other competitors were more covered up, the San Francisco resident was wearing nothing more than the blue trunks and a sizable backpack.

Five randomly selected audience members judged the costumes on level of detail, audience appeal, presentation, originality and creativity. Second and third prizes included gift cards, Sjaak’s chocolates and dinner at the storied John’s Grill in San Francisco.

Dominic Schmidt of Los Altos dances with his daughter Alexis, 7, during the Polar Bear Skate at Union Square holiday ice rink. (Harika Maddala/Bay City News)

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The Safeway Holiday Ice Rink has been a holiday fixture at Union Square for 14 years, and the Polar Bear Skate event began nine years ago, according to Robert Keith, the rink’s general manager.

“There’s a magic in San Francisco,” Keith said. “When people here have an opportunity to do something fun and outrageous, you can count them in.”

Larry Pascua and Natalie Renier-Bertolucci perform during the Polar Bear Skate contest at Union Square holiday ice rink. (Harika Maddala/Bay City News)

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Apparently, Bay Area residents threw themselves full-throttle into the event, upholding the revered San Francisco tradition of, “If you’ve got it, flaunt it.”

Keith said, “It started out, ‘Wear your favorite swimsuit attire and ring in the New Year.’ Then people started wearing homemade costumes.

Robert Keith, left, host of the at Polar Bear Skate contest and the general manager of the Union Square holiday ice rink, congratulates the contest’s winner, Joe Houston. (Harika Maddala/Bay City News)

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“We’ve seen costumes that had to have cost hundreds and hundreds of dollars. You never know what is going to happen — sometimes the bathing suits are very tiny,” Keith said.

Saturday’s contestants included a woman in a Batgirl cape and skaters clad in sarongs, a pink bathrobe and a silver feather boa.