It was a scene that wouldn’t have been out of place in a cinematic Taylor Swift song.

There was record heat. There were sudden and intense storms blowing through. The city teemed with celebrities from seemingly every corner of public life — from the actress Mariska Hargitay to the musician Ed Sheeran to the model Gigi Hadid to the comedian Adam Sandler, the wedding officiant — many of whom flew from across the world for Swift and her now-husband Travis Kelce without knowing almost any details about the event.

It was the most public setting one could imagine, and yet the most private celebrity wedding, in recent memory, of such a size, completely shrouded in secrecy. Manhattan was alive with sailors in town for Fleet Week, soccer fans visiting from the world over to watch the World Cup and tourists in town to see the tall ships in the harbor for the Fourth of July. The heat, which peaked at 100 degrees, also lent a level of intensity to the day.

The president commented on it, and little girls came from neighboring states to watch it. Only Taylor Swift, the woman whose songwriting has inspired fans young and old and whose love life the public has watched, criticized and cooed at over the years, could have a wedding that would bring together such a scene.

Outside Madison Garden, Zeinab Yassine, 13, from Long Island, watched a caravan of black vehicles ferrying guests to the wedding with her mother. Soon, she spotted Hargitay roll down the window to wave to fans.

Most of all, Yassine was happy for Swift and her then-husband-to-be Travis Kelce.

“They’re so cute,” she said. “I’m so happy she finally found love.”

There is an intangible thing that happens when groups of Swifties get together, even if they are strangers: an immediate bond, an easy shorthand talking about favorite songs, albums and boyfriends. It is like realizing you have a good mutual friend with someone you’re just meeting for the first time. Except, in this case, the friend is a megastar you have not technically met.

Tammy Bogard, a sales associate from Dallas, said she had attended the Eras tour in London, the first show after a thwarted terror attack in Vienna that forced Swift to cancel her shows there. The London show was an emotional experience for Bogard, 54, who said she was then just a burgeoning fan.

She was impressed by the show, but was even more moved by the crowd.

“It’s the other Swifties, that’s the thing you can’t describe to people,” she said. Bogard went on to see the tour again and now considers herself a full-fledged Swiftie, even giving a Times reporter a friendship bracelet, the wearable trinkets that are traded among the star’s fan base.

That friendly energy was present outside the Garden on Friday, as crowds of fans congregated hoping to catch a glimpse of Swift. At a barricade along Seventh Avenue, a group of fans sang “Love Story” while news cameras filmed them.

The list of celebrities spotted heading into the event was dizzying: Benson Boone, Ethan Hawke, Jason Sudeikis. Each had a connection to a song or to a chapter in Swift or Kelce’s lives. Boone opened for her on tour; Hawke starred in a music video and Sudeikis is a fan of Kelce’s team, the Kansas City Chiefs.

Shortly after 7:30 p.m., their nuptials became official when a sign broke the news outside the arena: “JUST&T MARRIED.” Not long after, the skies opened and poured down rain.

Soon, the White House weighed in with what appeared to be a slight: a post on social media with a digitally altered version of the sign outside the Garden saying, “Trump Is Your President.”

Her fans were buoyant. Two camp friends, Gray O’Sullivan, 18, and Frankie Root, 19, came to see the spectacle together. Root said that she had been at the Eras Tour and had loved Swift since 2014, when her album “1989” was released.

“She really understands me,” Root said. “When I’m having a hard day and I listen to her, it immediately makes me feel better.”

Sarah Mead and her 10-year-old daughter, Sunniva, who live in Brooklyn, were on their way to see the New York Philharmonic and stopped at the Garden with handmade signs referencing Swift’s lyrics: She will walk into M.S.G. and make the whole place shimmer.

“We’re hoping that Taylor will see us,” Ms. Mead said.

Not everyone was feeling that love outside the Garden, however,

Tyler Guilizia, a 23-year-old who was searching for a bathroom with his friend, asked police officers in front of the Garden: “Is this all for Taylor Swift’s concert — uh, wedding?” He gestured at the blocks of barricades.

Many streets were shut down around Penn Station, the busy train station beneath the Garden, annoying plenty of pedestrians and commuters, many of whom shouted at police officers to ask for directions and stormed off.

Fans also peppered officers with questions about the wedding. They did not offer details, but a female officer responded when fans asked her favorite song.

“‘Getaway Car,’” she said, smiling.

Eduardo Ramirez and Mamie Borres were standing on Seventh Avenue peering out at the Garden as the rain subsided on Friday night. Borres, 30, said she had been standing in front of the arena when the video screen flashed the marriage announcement.

“Not everybody noticed immediately,” she said. But then, there was a scramble of phones and cameras as excited fans filmed the sign, she said.

Soon after, thunder began to boom and rain poured down, forcing her to seek shelter.

After the storm, Borres, a teacher who lives in Alexandria, Va., returned to her post watching the venue in the hope of seeing, well, anything. West of the arena, the sunset colored the sky in glorious shades of purple and orange.

And lest you think there isn’t a Swift lyric for every occasion, may we direct you to her song “End Game.”

“After the storm, something was born on the Fourth of July.”

Sarah Lyon and Erin McCann contributed reporting.