Perfect holiday weather blanketed the metropolitan area yesterday, spurring thousands of Washingtonians, Virginians and Marylanders to head for the beaches and other attractions.

Police throughout the area reported extremely heavy highway traffic since Friday as great convoys of cars and campers streamed toward beaches, mountains and campgrounds.

Virginia State Police said yesterday a 15-year-old Harrisonburg, Va, girl was killed Friday night in a three-car crash on Rte. 122, about four miles north of Bedford.

Police in the nearby resorts of Rehoboth, Del., Ocean City, Md., and Virginia Beach, Va., all reported large crowds and bumper-to-bumper traffic.

"Weather-wise, it couldn't be better, crowd-wise, we're loaded, the beaches are jammed," said an Ocean City policeman seeming to summarize conditions in all three resorts.

For those who stayed closer to home, yesterday was a day to suntan along the banks of the Potamac, tour the Smithsonian Mall, or try to get to the National Zoo.

A Park Police spokesman said the zoo had been extremely crowded all day. "We've got wall-to-wall people up here. The parking lot's been full since mid-morning. There're about 17,000 people in the zoo now, but, of course, they've been coming and going all day," the spokesman said.

Nearly 48,000 vehicles crossed the Chesapeake Bay Bridge Friday and more than 35,000 were heading east toward the beaches, officials said. Nearly 80,000 vehicles passed through the Baltimore Harbor Tunnel. Yesterday traffic was reported moderate but moving slowly at both locations.

Most motorists on the road for the holidays can expect to find slightly higher gasoline prices, according to a survey made by the Maryland division of the American Automobile Association.

The AAA survey of Maryland gasoline stations found prices averaging 64 cents to 69 cents for regular to premium gasoline, a AAA spokesman said. The prices were an average of 5 cents higher than gasoline prices at this time last year.

Gasoline companies often raise their prices just before a major holiday or during the late spring, when there is certain to be more traffic on the road, the spokesman said.

In contrast to road conditions, traffic at National and Dulles International airports was light to moderate yesterday, according to airport police. They explained that most of the holiday crush had occurred Thursday and Friday and will occur again on Monday as the vacationers return.

Smithsonian officials said crowds were especially heavy at the Museum of History and Technology and the Air and Space Museum, two of the institution's biggest drawing cards.

The weather through the long weekend will remain warm and sunny with temperatures ranging from near 90 degrees during the day to about 60 at night."