NEW YORK -- The sky was sunny and the water was freezing at Coney Island, where several hundred people, cheered on by hundreds more, ran into the ocean Monday to mark the start of 2018.

While some dressed in dinosaur or penguin outfits, others wore nothing but underwear or bathing suits at the annual Coney Island New Year's Day Polar Plunge, a New York tradition since 1903.

"2018! The only way to start is in that cold water," Brooklyn resident Rosalia Perotta told CBS New York.

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"It started on my bucket list. It's a rush, a shock. It'll wake you up," said Louie Forte, 65, of Brooklyn, who took part in his seventh plunge. "This year is the coldest year yet."

People taking part in Coney Island's annual New Year's Day Polar Plunge race across the beach towards the water in New York, on Monday, Jan. 1, 2018. Peter Morgan / AP

With the temperature sitting at a frigid 17 degrees, some said the water was warmer, at 37 degrees.

Pete Johnson said it was a great way to start the year.

"I didn't know what I was getting into until last year," the 48-year-old said. "And I was just like, 'I'm going to do it every year.'"

Supporters stood by with towels and warm robes as the hardy souls returned from the sea.

"It was really great. My nose is running really bad," said Matt Ferraro, 30, donning a blue "Doctor Who" robe.

Allie Szyba, 32, was frantically rubbing her shoulders in an attempt to warm up.

"It's horrible, just horrible. It's not fun at all," she said laughing.

The event raises money for charities including, the Alliance for Coney Island, The New York Aquarium, and others.

Organizers raised $80,000 last year, when temperatures were about 50 degrees.

A Polar Bear Club swimmer carries an American flag as the group makes their annual icy plunge into the Atlantic Ocean on New Year's Day, January 1, 2018, on Coney Island in the Brooklyn borough of New York City. Yana Paskova / Getty Images

Dennis Thomas, president of the Coney Island Polar Bear Club, conceded that participation was down this year because of the cold, but he had no final estimate on how much was raised.

"Jumping into the cold water really kind of puts a period at the end of the sentence of 2017," said Thomas, who has been involved with the club for 30 years. Swimmers gather every Sunday from November through April, as well as on New Year's Day.