A teasing taste of fall-like temperatures drove work-a-day Washintongians from downtown offices to city street, sidewalks and parks yesterday.

They wallowed in a balmy break from summer's merciless 90 degree stride that had everyone smiling at everyone else or at no one in particular.

They said the weather made them do it.

"Oh, I know that it may get hot again tomorrow," said Lorraine Dreyfuss, who strolled along L Street with her husband, retired architect Edmund Dreyfuss, yesterday. "This weather is just great, it makes you want to go out and do something. You feel like kicking up your heels."

For the second day in a row, a mass of cool air hung over Washington, bringing relief from the stifling mugginess that dominated all but three days this month.

Yesterday's low temperature of 59 degrees - just four degrees warmer than the record low for the day - had many searching unexpectedly for light jackets and sweaters. The high temperature was 79 degrees.

In addition to the cool air, there were blue skies and sun, a combination that veterans of August in Washington find unthinkable.

A cool air mass moving northeastward from the Carolinas broke August's dog days Friday, contributing to heavy thunderstorms and rain over the weekend. Temperatures plumeted Friday from a high of 97 degrees to Sunday's high of 68, a delightful 29 degree drop.

"That's not something we usually experience in August," said meteorologist Jerry La Rue of the National Weather Service. "You call that a gift of nature."

As the cool air drifts northward, another cool air mass should descend upon the area from the southern Canada, keeping cooler weather her for most of the week, La Rue said.

"It's like a tast of fall," said Jackies Deitsch, an employe of the J. Walter Thompson advertising agency, as she sat with a friend in McPherson Square.

"Weather like this brings a feeling of newness, of freshness of starting all over and it make you feel happier."

District policeman Martin Bordell said, "with temperatures and humidity lower, people are a lot more hospitable...easier to deal with." Bordell was interrupted by a businessman in a gray suit who told Bordell unexcitedly that his car had been stolen on 17th Street NW during the day.

From her flower stand along Connecticut Avenue, vendor Gwendolyn McCutcheon said twice as many people seemed to be outside at lunch time as during the last several weeks.

"I'm selling more roses today, and that's partly because people are more appraciative on a day like this," she said. "Roses are an esthetic thing. If you are uncomfortable, you don't feel like buying."

At the Collector's Cabinet, a shop along Connecticut Avenue, clerks Kathy Walsh and Barbara Tomasso said the topic of the day was the weather.

"People are dressed differently today, they seem a little happier, and we are not usually as busy this early," Walsh said. "The weather brought them out."

"Last week, when it was in the 90s, I stayed at home most of the time where it is air-conditioned," said Minnie C. Simmons, a Northeast Washington resident and part-time dry cleaners employe. She sat on a wall underneath a tree on 16th Street NW, waiting for the G4 bus and basking in the 70-degree breeze. To her left sat a Garfinkel's shopping bag. "You know, weather like this just makes you feel happier, more optimistic."

Mary Johnson, a staff assistant at Americans for Democratic Action, said, "In the office today, people just seemed happier. They were telling jokes, they were smiling and everybody was talking about the weather.

"I was a lot happier today than on a typical Monday morning," she said, stopping her needlework and smiling at a visitor from her seat on the grass at McPherson Square. CAPTION: Picture, Chris Lehman of McLean found yesterday's breeze on the Potomac almost perfect for the serious sailor. By James M. Thresher - The Washington Post