Hop, a kangaroo at the National Zoo, lolled on his back in the afternoon sun while July-size crowds picnicked in shirtsleeve weather on the Mall and sales of antifreeze plummeted.

Washington waltzed toward winter yesterday with a near-record high of 66 degrees, four degrees shy of the 1927 high of 70. The city blithely ignored National Weather Service predictions that the coming season will be colder than normal.

"Whenever the weather gets warm, we just don't sell down jackets," said J. R. Wright, a salesman for an Eddie Bauer store on M Street that specializes in cold-weather clothing. "That's how people work."

Like the grasshopper in Aesop's fable who frittered away his time rather than prepare for the coming days of necessity, an unseasonably large number of Washingtonians took to the parks yesterday, ignoring sales on "auto winterizing," snow tires and ice scrapers.

The National Park Service reported "a significant increase" in visitors at all the area's national monuments and at Great Falls parks in Virginia and Maryland. Attendance at the zoo was more than twice the normal number for a winter Monday. Shirtsleeved fishermen encircled the Tidal Basin, joggers shed their warm-up suits to run in shorts and the lunch-time crowd at Haines Point rivaled those of summer.

"It could have been a warm day in July," said George Berklacy, spokesman for the park service.

But William DeMarr, retail sales manager for the Goodyear-Hecht's Tire Center at Montgomery Mall, had a lousy day. He was offering an auto winterizating deal for $17.88 that could save drivers $7. Only three customers asked for it all day.

"I don't think people plan," said DeMarr. "They don't seem to believe in preventive maintenance. It's only when it gets cold and starts to snow that they come in."

It may be another month before motorists begin to take winter seriously, according to Donald Gilman, a meteorologist specializing in long-range weather forecasting for the National Weather Service.

"Indications are that there will be a somewhat late start to winter in the Washington area," Gilman said yesterday. "But it is not at all unusual for December to be much warmer than the winter as a whole.

Gilman said temperatures of 70 degrees and higher are frequently recorded in the Washington area during the three months of the winter season, which the Weather Service official lists as beginning on Dec. 1. Winter begins officially on the shortest day of the year, Dec. 21, known as the winter solstice.

Gilman said that a warmer than normal December probably will give way to a colder than normal winter.

"The national weather pattern is one that indicates a 65 percent chance of colder than normal temperatures. But Washington will probably have less rain and snow than normal," Gilman said.

Yesterday's warm weather began to worry park service horticulturists assigned to look after the city's temperamental cherry trees. Four or five days of similar temperatures could cause premature cherry blossoms in March, when they could be nipped by the cold, according to park service spokesman Berklacy.

The weather service, however, had good news for the cherry trees. Temperatures today are expected to drop sharply from a late afternoon high of about 60, and the low tonight should be in the 30s. On Wednesday, the false promise of December will be belied by cold and partially cloudy weather with highs in the 40s.