Meteorologists said some Christmas Eve records could be broken by as much as 10 degrees.
"That's one thing about the temperature especially today - a lot of places will blow away their previous record highs," said Bob Oravec, a National Weather Service forecaster in College Park, Maryland.
Without the usual winter wonderland, some people clung to tradition to get in the mood.
Dozens skated at the ice rink in Cincinnati's Fountain Square, where the temperature was in the 50s. Many of them were part of the annual Mechley family Christmas Eve morning gathering.
"Ironically, it's the first year we had rented the warming hut," said Camille Gartner, who was part of the group, expected to reach up to 80 people spanning four generations.
Fran Convery of Valley Forge, Pennsylvania, tried to look the part, wearing red plaid shorts and a red pullover, but gave a bah-humbug scowl when asked about the weather. He was in Philadelphia with his family for a holiday tradition: looking at the decorations and having lunch at the Reading Terminal Market.
"I'd rather it be cold. I'd rather have snow on Christmas," he said. "This past week and the days leading up to it did not feel like Christmas with the warm weather. But when we start doing this stuff, it does."
In Warwick, Rhode Island, Stephen Malloney took advantage of the warm weather - the temperature hit a record of at least 65 in Providence - by playing a round of golf.
"Once I looked at the forecast, I packed my clubs," said Malloney, who was in town from Myrtle Beach, South Carolina, visiting family.
In New York City, the mercury hit 71 by 11 a.m. in Central Park, smashing the record of 63 degrees, set in 1996, and was expected to reach 74. The average temperature in December is just under 39 degrees. Dozens of people in shorts and tank tops went running in Brooklyn's Prospect Park.
"It's kind of like this is our little gift for the last two winters," said Carlie Buccola at the National Weather Service in Upton, New York.
The Associated Press