All over the Washington area yesterday were the signs of two seasons colliding.

In Arlington, Sue Harrison munched chocolate chip cookies on a bench near the courthouse. But she had a black wool coat over her shoulders and a gray scarf looped around her neck.

"I couldn't stay inside today. It's too nice," said Harrison, who handles tax refunds for the Arlington County treasurer's office. "I hope it stays this way, but with March, you never know."

Others defied the calendar by shedding their winter coats and February doldrums as the temperature at National Airport headed for a high of 67 degrees by midafternoon, about 20 degrees above the normal reading for Feb. 22 but 10 degrees below the record high for the day, set in 1874.

National Weather Service forecasters said winds coming clockwise from the south were whisking warm air over the eastern third of the country, and they predicted that the mild weather will last through the weekend.

As the mercury climbed to 57 degrees at noon, 2-month-old Michael Cassidy was having his first picnic.

Kathy Mullarkey of Alexandria sat on a yellow quilt on the Mall with her nephews Michael and Devon and her 2 1/2-year-old son Jamie.

Picnicking in February "is a little unusual," Mullarkey admitted as she unwrapped sandwiches. "But with three children, it's a lot easier than going to a cafeteria."

The grass on the Mall was still colored midwinter drab, but a bright parade of joggers, bicyclists, walkers and workers streamed through the area all afternoon, many with down parkas and wool scarves slung over their arms.

In front of the Air and Space Museum, a group of students from Gaithersburg Christian School left their jackets crumpled on the ground to toss and chase their newest souvenir -- a fabric Frisbee emblazoned with the museum logo.

Bronson Perry, clad like the rest in a pale blue shirt and navy pants with the surest harbinger of spring -- grass-stained knees -- said he knew how to tell it was not wintery anymore. Perry pointed to the tatters of a kite caught in a nearby tree. "They're not blowing at all. There's no wind," he said.

Three National Gallery of Art employes wheeled something resembling a 10-foot palm tree past the winter-stripped trees on Constitution Avenue.

Milton E. Vick, one of the workers, explained that the tree, with its clusters of bright green fronds, was actually a screw pine, a cousin of the palm family. It came by tractor-trailer from a nursery in Pompano Beach, Fla., he said, and the weather was perfect for its trip outdoors to the National Gallery's East Wing. "We were waiting for a nice day so we could bring it in."

If yesterday's temperatures were good for greenery, they also boosted some local businesses. Desai Bipin smiled as he directed a long line of mud-splattered Toyotas and salt-encrusted Chevys through the Shell Station's carwash on Wilson Boulevard in Ballston.

On nice days, Bipin explained, people want to wash the grime off their cars. Scanning several thick stacks of receipts, he estimated that 1,000 cars would go through the car wash by evening, 300 more than on an average day.

Bipin said the weather warms spirits, too, making customers more friendly and talkative. He patted his sweater and glanced at the sky, which had clouded once again.

"I put this on in case it got cold," he said. "But I feel warm inside."