Washington wore a pretty, cool face to the Cherry Blossom Parade yesterday.

The pale pink of chilled cherry blossoms cast a soft, pastel hue along Constitution Avenue as an estimated 100,000 spectators, a distinctive blend of Washingtonian and tourist, stood 10 deep at some points to watch in sunny, 45-degree weather.

In review, the parade was one of the largest-and the resulting traffic some of the most jammed-since this musical march through the Federal Triangle began 31 years ago.

Thirteen blocks of Constitution Avenue-beginning at Seventh Street NW and heading west toward the White House-was turned into something of a national Broadway.

High-stepping high school marching bands dressed in tails and plumes, novelty acts, ruffled, windblown floats, dancing girls and mounted patrols from across the country moved briskly toward the judge's stand from 11 a.m to 2 p.m.

A midwestern high school actors' troupe, dressed as Vikings, broke out in mock battle before the reviewers. Spectators cheered enthusiastically when they were threatened by the Vikings with axes, spiked balls and chains.

"It's the best parade we've ever had," said Greg Jennings, president of the city's Downtown Jaycees, the group sponsoring the National Cherry Blossom Festival.

"The blossoms are still out, even though many have lost some of their color. It seems that it gets cooler every year at this time, but it's still a real good day," Jennings said.

The blossoming of the famous Yoshino and Akebono cherry trees traditionally marks the unofficial beginning of spring in Washington. National Park Service horticulturists had expressed concern that occasional winds would strip the approximately 4,000 trees of their color and bloom.

Icy gusts that had severed tulip buds reportedly dropped to 20 miles an hour yesterday from a high of 53 miles an hour clocked Friday by the National Weather Service.

Parents hoisted children around their shoulders and necks to give the young ones a better view and perhaps to keep a little warmer themselves.

"Raise me higher, dad," one hefty toddler commanded a the El Toro float passed by. "That's enough," the boy concluded as the Markland Medieval Mercenary Militia moved in.

Vistors were treated to more than 100 floats and bands-from the Pink Panthers of Millinocket, Maine, to the Museum of History and Echnology and mobile posts along the parade route to ensure smooth passage to the reviewing stands.

"The parade is going real smooth," one radio operator said. "I wish I could say the same for traffic after this is over."

All north-south streets from Seventh to 17th Streets NW between Pennsylvania and Independence avenues were closed to motorists from 10 a.m. to 3:30 p.m. yesterday.

U.S. Park police reported that all bridges into downtown streets were clogged after the parade as motorists wormed their way back to suburbia. The jam was compounded by hundreds of chartered tour buses that made a smoky beeline out of town.

This year's turnout for the parade was the largest since the Bicentennial when an estimated 200,000 spectators lined Constitution Avenue.

In 1977, it rained on the parade and only 50,000 people showed up. The year 1975 was worse. Winds up to 40 miles an hour knocked out power lines and only 15,000 braved the cold that day. And 1974 was the pits. Only 5,000 people showed up for the parade as nearly three inches of rain pounded the area.

DelRio (Tex.) Queens. There were the Tell City (Ind.) High School band and the Maryann Woods Majorettes from Chesapeake, Va.

In a striking ensenble, the University of the District of Columbia float, topped by an attractive black queen, was escorted by shriners from the Kena Temple Mounted Horse Patrol of Alexandria.

"This is some kind of parade," said Michele Johnson, 18, a senior at Oxon Hill High School who worked a softdrink concession stand on the Ellipse yesterday.

"If only we had hot coffee to . . . " She said.

A company called American Public Events was hired by the Jaycees to put the parade together. A crew of 25 volunteer ham radio operators set up a command station in the Smithsonian CAPTION: Pictures 1 and 2, Billy Jordan, 4, left, of Arlington watches Cherry Blossom Parade while huddled under blanket; right trombonists lead as West Ottawa High School band of Holland, Mich., passes Monument.; Picture 3, Keith Wiggins waves flags as passing band plays "America the Beautigul" during Cherry Blossom parade. Photos by Joel Richardson-The Washington Post