On this warm, post-Labor Day weekend, Washington seemed caught between moods as well as seasons, unable to decide whether summer is really over and the fall has begun.

It could have been that after this first week of work and school since Labor Day, the town was exhausted. The usual weekend traffic jams around the Mall and tourist attractions were not bad, and tennis courts could be had at Hains Point without a wait.

With 90-degree weather intermittently cooled by gentle breezes, it was as though nature had pitted Southern humidity with Canadian gusts and let them play out the day to a tie.

Except for Georgetown, where celebrants observed the l67th anniversary of the writing of the National Anthem by former Georgetown resident Francis Scott Key, a spot check of city neighborhoods revealed sparsely filled parks and near empty streets.

"People still have a little taste of partying left in them," a U.S. Park Policeman said, surveying the spotty picnic crowd sprawled out on blankets near Hains Point. "But it's back to work for most of us."

Beyond the shoreline of Hains Point in the Potomac River, scores of others weekenders lay on the decks of sail boats, basking in the brilliance of the day, savoring the last rays of summer.

Over at Lafayette Square, however, the autumn protest season was underway.

Among the opening acts was the Committee of Friends and Supporters of Libya, who had congregated in a circle across Pennsylvania Avenue from the White House to protest the recent downing of two Libyan jets by American F-14 Navy fighters.

The crowd of about 500 chanted in Arabic, "Leave Africa for the Africans." About 12 Trailways buses had brought the Libyans to the park from National Airport. Some claimed they had been flown in from Libya.

The atmosphere along Georgia Avenue also hinted at the coming fall season.

The Howard University Bisons opened the football season as brightly dressed crowds waved pompons, and the beat of bass drums and tubas could be heard on the streets outside the stadium.

A palm reader seated at an incense stand among the beverage vendors near the football game correctly predicted the winner of the game (Howard beat Cheyney State 33 to 23) and added that the weather today would be as nice as yesterday.

The palmist also noted that if yesterday was your birthday, you are attractive, enthusiastic -- and older.

For their part, Washington area weathermen predicted that the palm reader's prediction was as accurate as her football forecast. They say the temperatures today will be mostly sunny and continued warm with the chance of rain near zero.