PORTLAND, Maine — A teeth-chattering cold wave with sub-zero temperatures was expected to keep its icy grip on much of the eastern U.S. into the weekend before seasonable temperatures bring relief.

A polar air mass blamed for multiple deaths in the Midwest moved into the Northeast on Wednesday, prompting the National Weather Service to issue wind chill warnings across upstate New York and northern New England and creating problems for people still trying to rebound from superstorm Sandy.

In a storm-damaged neighborhood near the beach on New York City’s Staten Island, people who haven’t had heat in their homes since the late October storm took refuge in tents set up by aid workers. The tents were equipped with propane heaters, which were barely keeping up with the cold, and workers were providing sleeping bags and blankets for warmth.

Eddie Saman is sleeping in one of the tents because the gaping hole in the roof of his home has rendered it uninhabitable. Heat has been restored to the house, but much of it escapes through the hole.

“It’s very cold,” Saman said, “and mainly I sleep here next to the heater here.”

The Canadian air mass that arrived in the Upper Midwest during the weekend forced schools to close, delayed commuter trains and subways and kept plumbers busy with frozen pipes.

A ski resort in New Hampshire shut down Wednesday and today because of unsafe ski conditions — a predicted wind chill of 48 degrees below zero.

The coldest temperatures were expected Wednesday and today, after which conditions should slowly moderate before returning to normal, said John Koch, a meteorologist with the National Weather Service regional headquarters in Bohemia, N.Y.

For the most part, temperatures have been about 10 to 15 degrees below normal, with windy conditions making it feel colder, he said.

In northern Maine, the temperature dipped to as low as 36 below zero Wednesday morning. The weather service was calling for wind chills as low as minus 45.

For Anthony Cavallo, the cold was just another in a litany of big and small aggravations that began when superstorm Sandy swept through his Union Beach, N.J., neighborhood and flooded his one-story house with 41/2 feet of water.

Still waiting for the go-ahead to rebuild, Cavallo and his family have been living in a trailer they purchased once it became clear they couldn’t afford to rent.

Wednesday’s frigid temperatures temporarily froze the trailer’s pipes, which Cavallo’s 14-year-old daughter discovered when she tried to take a shower at 4:30 a.m. Cavallo spent the morning thawing out the pipes and stuffing hay under the trailer to help insulate them.

“Every day it’s something, whether it’s frozen pipes or getting jerked around for two months by insurance companies,” the 48-year-old security system installer said. “I just kind of want to wake up one day and have no surprises.”

In New York City, food vendor Bashir Babury contended with bone-numbing cold when he set up his cart selling coffee, bagels and pastries at 3 a.m. Wednesday. On the coldest of days, he wears layers of clothing and cranks up a small propane heater inside his cart.

“I put on two, three socks, I have good boots and two, three jackets,” he said. “A hat, gloves, but when I’m working I can’t wear gloves.”

A little cold air couldn’t keep Jo Goodwin, 64, of Bridgewater, N.H., off the slopes at Sugarloaf ski resort in Carrabassett Valley, Maine, where she was skiing Wednesday with her husband and her sister. The snow conditions were great and there were no lift lines.

To keep warm, she uses a toe warmer, a hand warmer, a face mask, extra underwear and an extra wool sweater. She was told the wind chill was minus 30 midway up the mountain and 50 below zero near the top.

“Sometimes,” she said, “it’s better not to know.”