Christopher Payne, 15, decided two things yesterday. One, the long, cold winter really had ended. Two, Washington has somehow managed to skip spring.

"Summer's here." Payne insisted, stradding his bicycle and surveying the throngs of people on the grounds of the Lincoln Memorial, "and I hope tomorrow will be the same."

Seventy-four degress, said the National weather service, a temperature fully 10 degrees higher than normal for this time of year. That, combined with the cherry blossoms, Tidel Basin sailboat races, demonstrations, crew races and waiting ball fields proved irresistable attrative to washington area residents.

About 30 people gathered under the beaming sun on the steps of the District Building yesterday morning both to denounce Mayor Walter E. Washington for not doing enough for the elderly and show their support for one of the candidated for mayor in this year's Democratic primary, John Ray.

The John F. Kennedy League for Universal Justice and Goodwill organized the rally and its president, the Rev. Hosea Browne, urged the mayor to "stand up and speak for the senior citizens of this city, like he stands up for his aide (Joseph Yeldell)."

Not far away, several hundred demonstrators from Arlington crossed Key Bridge and marched up Pennsylvania Avenue to the White House. They wanted an absent Presicdent Carter to change his mind about Pte. I-66.

Ballons, Bicycles and poster-bedecked children lazed in Lafayette Park, as the 20-year-old litany against the highway was recited once again. The marchers were so energetic that they arrived at the park an hour earlier than planned> and passed the time singing new wrods to old protest songs like "Blowing In The Wind.

"How many trees will the highway destroy, how many people displace?" sang the marchers. The answer lay in a long line through Arlington County where trees have been cut and the grading begun on the highway which will stretch from the Beltway in Fairfax to Theodore Roosevelt Bridge.

"Those of us involved in this struggle have seen our children grow up and our parents grown older," said James Govan who formed a citizen's group that almost singlehandedly stopped the highway in tis tracks earlier in the struggle. "The only way to look at it is until they actually build I-66. There's still hope."

It had been hoped that more people would show up for the march, despite mounting odds against preventing the highway's completion. But there were many things to do on such a Saturday. "My best friend was going to come," said Arlington resident Flora Roth. "But she's out helping to save the YWCA."

And if you didn't want to save I-66 or criticize the mayor or save the YWCA, you could have joined several thousand demonstrators who took part in a Youth March For Jobs, many of them balck teen-agers from New York Cuty and Philadelphia.

The demonstrators - estimated at 10,000 by march organizers and at 1,500 by U.S. Capitol Police - walked from the Lincoln Memorial to the Capitol, carrying banners attacking the Carter administration for not doing enough to reduce youth unemployment.

The march was strongly supported by the U.S. Communist party, and also won endorsements from a wide range of other groups, including the Young women's Christian Association, the Young Workers Liberation League, several labor unions and the D.C. City Council, which passed a resolution endorsing it Tuesday.

Council member Hilda Mason, a featured speaker, declared at the rally: "The large coporations are swallowing up all the wealth is not owned by all the country and the world. The wealth is not owned by all the people but by the large corporations."

D.C.'s Spingarn's 40-member marching band and its majorettes and pom-pon girls took part in the march.

However, Washington school superintendent Vincent E. Reed said in an interview later that he had not endorsed the school's participation and had not been told about it. "I'll have to investigate," he said. "We try to stay out of politics."

Despite the numerous marches and rallies, however, yesterday seemed for most area residents just a good day to be outside, either to participate in mass volleyball games or sit propped against a tree with a book and a bag of potato chips or throw a frisbee to a friend.

It was not such a good day to study, said those Georgetown University students at the edge of the Tidal Baisn.

"We came here to study, but we haven't done much of it." admitted Lori Vien of Houston and Dana Galullo of Connecticut. "Ir seems like we've stopped to take pictures of every tree er've seen." This was the first time this year they had been to the Tidal Basin to see cherry blossoms, they said, and warm weather is here to stay. "It better be," added Christine Leuthold of Connecticut. CAPTION: Picture 1, After the long walk from Key Bridge to Lafayette Park to protest I-66 [WORD ILLEGIBLE] gets a ride, By James A. Lebraze - The Washington Post; Picture 2, Youth March for Jobs demonstrators arrive at the Capitol,; Picture 3, while Fred Berner and son, Freddie, check cherry blossoms, By Bob Burchette - The Washington Post; Picture 4, Part of the crowd marches toward Lafayete Park to protest building of I-66 before the White House but President Carter was absent, By james A Parcell - The Washington Post.