Leave it to Mister Rogers to make sure Washington had a sweater on the coldest day of the season.

Fred McFeely Rogers left public television's "Mister Rogers' Neighborhood" long enough yesterday to donate his red zip-up cardigan, the one he's changed into so many times at the beginning of his children's show, to the Smithsonian.

"Welcome, all of you today," he said in his famously gentle voice during a brief ceremony at the National Museum of American History. "It's certainly a very beautiful day in your neighborhood of Washington."

The host of the award-winning series had been preceded by a videotaped version of his famous entrance and change of wardrobe, the one where he doffs his suit jacket and shoes for sweater and sneakers.

"You can't beat that for an invitation to Americans to feel comfortable with a public figure," said a beaming museum director Roger G. Kennedy, who looked like he'd always wanted a neighbor just like him.

The public figure, on the other hand, seemed anything but comfortable in the spotlight. His delivery was slow and careful. "I feel particularly grateful today because I think that everybody longs to have something of value to give in this life, and you here have told me that I have something of value in the work that I do," he said.

"I'd like to think that I represent children and wounded people, people who may feel that they don't have much to give," Rogers continued. "What I like to be able to offer is the sense that you really do have something -- it's yourself. And when I tell the children near the end of the program, 'You've made this a special day by just your being you, there's only one person in the world like you and people can like you exactly as you are,' I mean that. I've met a lot of children, and children have taught me a great deal, and I've tried to give that back to them."

Mister Rogers -- the name has a compelling unity, like General Patton or Count Basie -- actually donned the cardigan briefly, recalling that his sweaters were all made by his mother, who died two years ago. "She used to make a sweater every month and there were 12 of us at Christmas who would get one. Mine was invariably a cardigan."

Described by Kennedy as "a friendly artifact," the red cardigan will join other symbols of Americana at the Smithsonian.

Why did he donate the red one? Rogers was asked. "The cameras at WQED are too old, they can't take the color red." Don't worry, though. He will not go cold into that good studio: he has another dozen, in different colors, at home in Pittsburgh.

As he was cosigning the formal deed of gift to the nation with senior curator Carl H. Scheele, someone asked Rogers what fabric the sweater was made of. He didn't know.

"Could you tell if you felt it?"

"This is the last time this sweater will be touched by a member of the American public," Kennedy announced, in mock-stentorian tones.

"I didn't realize it's not mine anymore," Mister Rogers said, slightly embarrassed. When even the touch test wouldn't reveal the fiber, Mister Rogers offered to check things out back at home. "If you would give me your address . . ."

Of course, it's exactly that kind of caring and directness that has endeared Mister Rogers to millions of viewers over the years. The sweater thus becomes more than another nice artifact. It's also a symbol.

"I'm not sure that I knew it at the beginning, but I do feel now that it's a symbol of 'I'm going to stay a while, let's just settle in and have at least a half an hour visit together,' " Mister Rogers said. Settle in, he has: yesterday's ceremony also celebrated his 30th year in children's programming, as well as public broadcasting's 30th anniversary. It all started with WQED in Pittsburgh, still the site of "Mister Rogers' Neighborhood."

Mister Rogers recalled his early years on television, including the first eight when he was not seen on camera (his puppets were the stars then). He also insisted that he didn't mind the occasional caricatures -- "These people seem to have a real affection for me."

He said he once met comedian Eddie Murphy, who does a "Mr. Robinson" bit, in a hallway, Murphy squealing, "The Real Mister Rogers!" and the real Mister Rogers answering "The Real Mister Robinson!"

He added that his major hope has always been "to give children one more honest adult in their lives."

The sweater will go on display in the "Nation of Nations" exhibit later this year.