It was a day for playing Frisbee in shorts after final exams, for going to the park without mittens, for eating lunch at a sidewalk cafe in summer sandals instead of winter boots.
Yesterday, Baltimore woke up to sunny skies, and the temperature climbed to 72 degrees by early afternoon, setting a record for the date at Baltimore-Washington International Thurgood Marshall Airport.
The last time BWI recorded temperatures anywhere near this warm on a Dec. 18 was in 1984, and even then it was only 69 degrees. It also was the warmest Dec. 18 at Washington Dulles International Airport in Northern Virginia, where it was 76, smashing a 69-degree record set in 1984.
Until about 4:30 p.m., when the winds kicked up and the sun began to dip, people throughout the region were finding a way to enjoy Mother Nature's last gift of the season.
Minutes after Johns Hopkins University senior Laura Kaplan returned her library books, the New Jersey native was on the campus' grassy "beach," pulling off her sweat pants to play Frisbee in shorts and a T-shirt. Kaplan, who is on the school's Ultimate Frisbee team, said the women usually don't play this time of year because of the cold. But when teammates saw the weather report, they sent around an e-mail and quickly organized a pickup game.
"Finals are almost over," she said. "I'm almost done, and it feels really great to play Ultimate Frisbee."
Nearby, Patrick Kay had been on winter break for "about seven minutes," since taking his last final. He was sitting on the grass in shorts and a T-shirt.
His friend, James Lee, was supposed to be studying, but he was using his physics book as a pillow and reading The New York Times. "Maybe he'll learn by osmosis," Kay joked.
Asked why it was so warm out, sophomore Nirosha Mahendraratham didn't hesitate. "It's global warming," she said.
Meteorologists have another explanation for the unseasonably warm weather.
"The jet stream has been ... locked up in Canada, north of the eastern part of the U.S., which keeps the cold air locked up, as well," said Jeff Warner, a meteorologist with Penn State Weather Communications.
Most of our weather this month has come to us straight east from the Pacific Ocean, he said. "At this time of year, while it is approaching winter, if the air has its origins over the Pacific, it really is not that cold."
Yesterday was the second time this month that the mercury at BWI has topped 70 degrees. It reached a record 75 degrees Dec. 1. Five years ago, December produced three days of 70-plus weather during the first week.
Even so, Lee Griffith couldn't remember the last time he was up on a roof in December without several layers on.
Griffith, who works for a roofing company, was standing five stories above the ground yesterday atop the new Catholic Charities building on Fallsway, where the temperature was about 15 degrees warmer than it was at street level. He'd come to work in a winter coat and hoodie, but was wearing just a lightweight sweat shirt as he took a break from installing the building's metal roof.
"Somebody lied to us," Griffith said as he ate a cup of bean soup and a sandwich before climbing back up to finish the job. "This ain't December. I could deal with this the rest of the year."
But it all was expected to came to an end overnight, as a weak cold front made its way south from eastern Canada into the Mid-Atlantic region. While it was 70 degrees yesterday afternoon in Baltimore, temperatures were falling through the 40s in State College, Pa.
"It will still be slightly above normal tomorrow [in Baltimore], probably in the low 50s," Warner said. "But it certainly isn't going to be 25 degrees above normal."
That's news to warm Renee Fries' heart.
Yesterday, the Baltimore County nurse asked her waiter at Donna's if she could move to an outdoor table that wasn't in quite so sunny a spot. Fries hadn't thought that being too hot would be a problem - she was dressed in a short-sleeve linen shirt and summer sandals. Already perturbed about having to turn on her air conditioning in December, she was hoping the warm weather wouldn't last much longer.
"What if I can't have a fire in my fireplace at Christmas? I'll be so mad," she said.
In Rodgers Forge yesterday, the only signs of Christmas weather were the fake icicles hanging from roofs. At the playground, it was warm enough for children to play in their shirtsleeves. No one had to ask them to button their coats or wear their mittens. Many a nap was postponed because the little ones didn't want to leave, and their parents didn't want to, either.
"This is the last blip of winter warmth," said Nicole Mazurek shortly before she carried her sleepy son, Ashton, out of the sandbox so they could get back to their Parkville home for his afternoon nap. "It feels like we're in California."
Mazurek came to the park with Ashton and her daughter, Kelsi, after Christmas shopping in Towson.
"When they heard we were coming here, they jumped up and down," she said. "They ran from the car here. My kids are very outdoorsy people."
Nearby, Joanna Noppenberger of New Freedom, Pa., was helping her son, Brian, go down a plastic slide.
"We were down here for a dentist's appointment, and it was too warm to go home," she said.
However, young Brian is a little worried about Christmas, his mother said. "I told him it has to get cold so the reindeer can come down."
Christopher Emery Sr., the lone dad at the playground yesterday, was building a sand castle with his 5-year-old son. It was the sort of day he doesn't expect to see again, inside or out - he works in a dairy and spends most of his days in a 35-degree warehouse.
"When you get a chance to do this, you're like, 'yeah!'" Emery said. "When it's nice like this, everybody's in a better mood."
Sun reporter Frank Roylance contributed to this article.