They don't call it the polar bear plunge for the balmy weather.

But this year, an especially frigid New Year's Day forecast has towns up and down the Jersey Shore canceling or postponing their annual traditions.

Citing fears of frostbite and hypothermia, organizers of the plunges in Margate and Brigantine joined their counterparts in Ocean City and Ventnor in calling off Monday's festivities because of the deep freeze gripping the region.

But in Atlantic City, the plunge will go on.

As of Friday, the casino-resort town was still planning for the event, according to the Mayor's Office and the Atlantic City Polar Bear Club's Michael Kahlenberg.

The high at the Shore is expected to only reach 21 degrees on Monday, the National Weather Service says. On Friday, the ocean temperature was just below 40 degrees, according to the National Centers for Environmental Information.

Kahlenberg, who has run the Atlantic City event for 30 years, said he wasn't concerned by the forecast.

"I'll be perfectly honest, the majority of people who go, they run in to their ankles. They scream and holler, and they run out," Kahlenberg said. "The event starts at 12 o'clock and ends at 12:01."

Atlantic City's plunge usually draws 250 to 400 participants, from ages 6 to 80. But with other towns canceling or postponing, "we could do better," Kahlenberg said.

Folks who usually take part in other towns' plunges have already called Kahlenberg to inquire about Atlantic City's, he said. Since people can register until Monday, he said, he does not know how many will come out this year.

As for emergency personnel, Atlantic City Fire Chief Scott Evans said the department was planning for business as usual, with about a dozen firefighters, police, and EMS workers on hand.

"For Atlantic City," Evans said, "this is not a big event."

And, compared to other plunges, it is relatively tame, with not as many outdoor pre- and post-plunge festivities as some other towns such as Margate.

"Atlantic City doesn't have the tailgating," Evans said. "It doesn't have the beach party."

In A.C., participants stay inside the Landshark Bar & Grill until about 10 minutes beforehand, run into the ocean for maybe 30 seconds, and then dash back into the bar, Evans said.

Plus, most people don't fully submerge themselves in the ocean, he said.

"That's one of the biggest dangers -– putting your head underwater and getting that cold shock," Evans said.

This year's event isn't for everyone, he cautioned. Evans said he advised small children and the elderly to sit out this year's plunge. Those with medical problems – particularly heart, blood pressure, or mental-health conditions – also should not run into the cold water, Evans said.

Both he and Kahlenberg said there has never been a serious medical emergency at their city's plunge. And, Kahlenberg said, "we've gone in with conditions as bad."

Evans doesn't anticipate the weather's having a negative effect on turnout. Once it reaches a certain temperature, he said, it just feels cold.

"Whether it's 30 degrees or 5 degrees," Evans said, "you're going to go down to do your traditional New Year's dip."

While Ventnor and Ocean City have not rescheduled their plunges, the nonprofit Brigantine Polar Bears now plans to hold its ocean challenge on Jan. 13. Robert's Place, the local bar/restaurant that sponsors the Margate event, is aiming for Jan. 7.

Robert Sutor, whose father owns Robert's Place, said no one has experienced a medical emergency at Margate's plunge since it began in 1993. They canceled in part, he said, because they didn't want to break that streak. "God forbid something bad happens," Sutor said, "that wouldn't be fun."

Robert's Place still will hold a New Year's Day party, he said, but it won't involve any sanctioned runs into the ocean.