Taylor Swift has spent years training her fandom to look for clues in her work, to sleuth for Easter eggs and find details hidden in plain sight.

On Thursday outside Madison Square Garden, fans had to look hard for any hint of the pop star and her fiancé, Travis Kelce, who are hosting a multiday event at the arena around their wedding this weekend.

The couple invited about 100 people to a rehearsal dinner at the Infosys Theater, a venue inside the Garden, on Thursday evening, according to an internal police memo previously reported by The New York Times, with details about the gatherings. The memo is titled “Taylor Swift wedding at Madison Square Garden.” Thursday’s dinner was a prelude to a larger 1,000-person event on Friday.

Like other brides, Swift was dealing with a dreaded unpredictable element of wedding planning: the weather. Her wedding weekend coincides with a heat wave in New York City and temperatures of 100 degrees or more.

When Taylor Swift sang “keep it 100 on the land, the sea, the sky,” in her song “The Fate of Ophelia,” she probably didn’t mean it so literally. Outside the Garden on Thursday evening, passers-by, fans and police officers alike were visibly dripping sweat in the oppressive heat. Some stopped to take photos of the arena and the driveway where several S.U.V.s with blacked-out windows entered as the 6 p.m. start time approached.

Elsewhere in the city, friends of Swift and Kelce were being spotted — Selena Gomez posting from her car, Lena Dunham with a window rolled down, Chiefs players at the airport, Camila Cabello and Dua Lipa leaving a recording studio. Swift’s longtime collaborator Jack Antonoff and his sister, the designer Rachel Antonoff, were seen looking dressed up, and the actor Bradley Cooper and the model Gigi Hadid were also seen in New York City. But outside the venue, fans wishing the couple well waited at barricades with views mostly taking in a garage space.

Kate Huesken and her two roommates stood behind the barricades, clutching suitcases and mulling where to grab a drink as they waited for a delayed train. The trio, all Swifties, discussed what the singer’s wedding dress might look like.

“I don’t think she’s going to do poofy,” Laney Leach, who is 23 and works in fashion, said, adding that Swift’s style had varied widely over the years.

Huesken, a 23-year-old marketing assistant who lives in the East Village neighborhood of Manhattan, said that she worked nearby and that she and several colleagues had come down on other days this week to scope out the scene. She thought Swift might wear something with a corset top by the designer Vivienne Westwood, who dressed Swift during the Eras Tours.

A small crowd gathered on the street in front of Life Time fitness to try to steal a glimpse, though there wasn’t much to see. A crew unloaded wrapped objects from a semi truck, and there was a little — if only just a little — relief from the heat as the sun dipped behind the buildings.

Audrey Walsh and her mother, from Connecticut, had stopped by after a day at dance camp. Every time a new, wrapped object was unloaded from a semi truck, Audrey, 14, would exclaim, “That’s Taylor Swift!” She was serious, she told her laughing mother, reminding her that Swift was known to have surreptitiously entered venues during the Eras Tour by hiding in an oversize cleaning cart.

Alyssa Heinen and Lindsey Bongiorno said they had visited the Garden already that day in hopes of seeing Swift, but had mostly seen police officers with large guns and dogs.

“We’re planning on coming back tomorrow morning,” said Bongiorno, a 25-year-old public relations assistant who lives in Byram, N.J. “We think, realistically, Taylor’s going to get here early.”

Ryan Weng, 25, stood nearby wearing an Eras Tour shirt, a “Reputation” ring and a friendship bracelet beaded with the word “Lover.” Growing up in China had prepared him for today’s extreme weather, he said.

“I’ve been listening to ‘So High School’ today,” Weng, who lives in Downtown Brooklyn, said, referring to a song many Swifties believe is about Kelce.

On 31st Street, people were arriving in cars and Sprinter vans with tinted windows to enter the Garden through a tented entrance. Three patrons at O’Briens, an Irish bar across the street, peered out the window trying to see who might be entering the event. The bar had a special menu: One could order the “Love Story Martini” or “Style Sangria,” nods to Swift’s songs.

Mike O’Brien, the bar’s owner, expressed frustration about the barricades and the police presence surrounding his business and making it difficult for would-be patrons to enter, particularly on a night with a World Cup match, which would typically bring crowds for the big-screen TVs.

“We are open, but you have to beg, borrow and steal to try to get down the block because of the wedding,” O’Brien said on the phone to a caller asking if there was still space inside to watch the match. The bar was almost entirely empty, save for a handful of journalists, police officers and people wearing blue wristbands that appeared to be related to the Swift party. Later in the evening, a bartender announced that the bar would be closed the following day because of Swift and Kelce’s event.

Cars depositing people at the Garden drove into a white tent on 31st Street where curtains were closed behind each vehicle to obscure the view of who might be arriving and then reopened to let in the next vehicle. Tourists leaving Penn Station grumbled about the street closures and the crowds.

The no-phones rule at the events has constrained guests, but before the big day, there were some glimpses.

Earlier in the week, semi trucks and forklifts were delivering and loading in objects covered in dark plastic, some the size of a car. Small gaps revealed leaves and trees. A forklift driver had a T-shirt that read, “Taylor Swift CARPENTERS.” On Thursday afternoon, a group of women carrying hard cases that appeared to be housing string instruments entered the building. A truck from a party rental company was also spotted nearby.

On Wednesday, Alicia Griffith, 51, and her daughters, Althea, 10, and Cora, 12, who had traveled from Piedmont, S.C., added a spontaneous stop at Madison Square Garden on their vacation. “You read things online, and I’m like, ‘Let’s go see for ourselves what’s happening,’” Alicia said. The plans to visit New York were made without the wedding in mind, but it seemed to be kismet: They had already booked a walking tour of Taylor Swift’s New York for that day about a month ago.

“So really,” she said, “Friday has always, on our itinerary, been our Taylor Swift day.”

Gabriella Gershenson and Nate Schweber contributed reporting.