The mood has settled at the swimming pools and recreation halls that once brimmed with contentment but now are touched by the melancholy of a summer's end. It is most acutely felt at the shopping centers where the kids came for sodas or records or suntan lotion but now trudge in for creased shirts and shoes that are somehow always too shiny and stiff.

For thousands of children returning to school in Maryland and Virginia this week, Labor Day week end is the most bittersweet time of the year, an occasion when they are rudely reminded that freedom from a daily regimen of clocks and books is only a summertime thing.

To them, Labor Day marks the practical close of summer and a return passage to winter routine.

"I've had it. I quit. My mother's taken me all over the store but I just can't go any further," lamented ninth-grader Tim Giere, who spent the summer swimming and surfing at Rehoboth Beach but yesterday sat forlornly in the middle of a stairwell at a Montgomery Mall department store.

He rubbed the gleaming black boots that were already blistering his feet and concluded, "School's gotta be the last thing on my mind."

It was an assessment shared by dozens of others who reluctantly sampled new winter shoes and clothing at Montgomery Mall yesterday, including Whitman High School student Sharon Barr who frowned when a clerk showed her a pair of suede saddle shoes.

"It's culture shock, really," she said. "I spent all summer traveling through Israel and living on a kibbutz. School is a pretty depressing thought compared to that."

Lucinda Shelton, meanwhile, said she had long ago given up school shopping when her children -- aged 42, 34 and 32 -- moved out of the house. Yesterday, though, she returned to the annual routine to "put some clothes on my grandkids' backs."

"When my kids grew up I tore up all the credit cards and said amen," she said, sifting through a shelf of shirts at Hecht's. "But I've got a 12-year-old grandchild who looks like a beggar."

Many teen-agers, however, were determined to celebrate summer to its very end. Swimming pools were crowded with kids seeking last-minute tans, while more than 10,000 people congregated on the Mall to partake in a giant frisbee contest sponsored by the National Air and Space Museum.

"Well, think about it," demanded 16-year=old Shelia Baxter, who clung to the edge of the swimming pool at the Bethesda YMCA. "For the next nine months of my life, when am I gonna have time to sit in the sun? When I go back to the books, I'll go in style."

Six-year-old Tommy Crown agreed. He sat in the Sears shoe shop with four sisters yesterday and proudly displayed the cast he wore over the wrist he broke during the summer.

"I fell from a tree during war games," he said, adding that he could not wait to show the injury to his fellow first-graders.

Lifeguard Doug Linscott, a Whitman High School senior, really wanted to go back to school in style but a wedding shower, of all things, got in the way.

He reclined on a bench yesterday outside the YMCA and comisserated with a friend about his last night of freedom, which he wanted to share with his girlfriend.

"My last night, man, my last night," he cried. "I was gonna take her out on the town and she says she's gotta go to a shower. What a pain."

Linscott said the girl will attend a private school this year, and he was not sure when he would be able to see her again.

"I've only known her for four days," he said, hands outstretched. "Of all the bikinis around here, she was by far the best."