Part of a series of stories calling into question the supposed joys of summer.

“Summer fling, don’t mean a thing,” Danny Zuko sings in “Grease” as he pops the collar on his leather jacket, bragging to his friends about hooking up with Sandy Olsson. Their summer fling is thrilling, intense, a chance to date someone outside their usual social circle. It seems fleeting at first, but gee whiz — it actually works out for these two! As the movie ends, the couple drives off into the clouds and their friends down below croon about how “we’ll always be together.”

“Grease’s” songs are still infectious, but the story is several generations out of date. Danny and Sandy met in a fictional 1958; the film was released in 1978. Back then, a fling was an exciting break from a reality where committing at a young age was common.

As seen through countless movies, a few TV shows and one song, this is a re-telling of a summer fling. (Nicki DeMarco/The Washington Post)

Now, however, flings abound. You don’t need to happen upon a cute lifeguard or carry a watermelon into a rousing party in the Catskills to find one. All you have to do is hop on a dating app. Wherever you are, someone is always in town for just a little while — traveling, interning, trying to get their life together — and short-term romance is no longer a break from routine. In the Tinder era, it is the routine. As a result, the summer fling has become more tiresome than thrilling — yet another relationship that’ll inevitably cool off and leave you burned.

No one knows this better than recent college grads. On a Tuesday night in Adams Morgan, three girlfriends gathered at a rooftop bar to celebrate one woman’s new job and another’s impending study abroad in Barcelona. They’re young (21 to 23), which could be the ideal age for a no-strings-attached romance. But they’re wise to the scam that is the summer fling.

“It’s fun until you catch feels,” 21-year-old Allie Raps says, using the Calvin Harris lyric. Like many her age, she’s so uncomfortable with having feelings for someone that she can’t pronounce the word in full. “The only problem is it ends at the end of the summer.”

Last summer Raps met a guy who was in Baltimore, where she lives, for just the season. He was a friend of a friend; she was bored while taking summer school classes. Together, they watched a lot of “It’s Always Sunny in Philadelphia” and drove to Assateague to see the wild ponies. She was starting to feel attached. He, on the other hand, felt so free that he made out with one of Raps’s sorority sisters right in front of her — during Raps’s birthday celebration.

“I really thought all y’all were going to kill him,” Raps says of her girlfriends’ reaction.

Cece Freed, one of Raps’s friends, says a summer fling “only goes bad if there are mismatched expectations.” And boundary-setting conversations are probably not happening as the Ferris wheel turns or as fireworks explode.

That summer glow can be deceiving. It seems like the perfect time to enjoy a few steamy nights. People are staying out later, relaxing more, wearing less. You meet people you wouldn’t normally — the girl at camp, the guy by the hotel pool. Serendipity is an aphrodisiac. “The novelty of a summer experience will drive up the dopamine in the brain and make you more susceptible to falling in love with a person,” says Helen Fisher, a biological anthropologist and expert on love.

“You’re playing with fire,” Fisher says of summer flings, because even casual relationships can spark serious feelings. “You can go into what you think is just going to be a fling, and sure enough, at the end of the summer the person disappears, you disappear — and you’re left with one of the most powerful feelings on Earth.”

If you feel let down by Labor Day, the effects can linger. “It’s going to take you quite a while to recover,” she says. “And of course while you’re recovering, you’re less likely to meet somebody else.”

Luis, a 29-year-old gay man from the Dominican Republic, is in that ambiguous stage where he and his fling are now oceans apart but are still trading daily WhatsApp messages, calling one another “muffin" and “cupcake.” Luis spoke on the condition that only his first name be used because he’s not fully out when he’s at home. But on vacation, he feels freer to flirt. And on a recent trip to Portugal, he met an attractive man at a bar. They spent two blissful days together and are planning to meet again in Croatia in December.

But Luis knows that summer flings can be fickle and is trying not to get attached. “It all comes down to decisions and if you’re willing to commit,” he says while standing on a street corner in Washington on a visit to see his cousins. Luis says he doesn’t have any expectations about where things will go with his fling, but what if the winter trip doesn’t come to fruition? A lot can change in two seasons.

Claire Shefchik lives in a place where it’s summer all year long: the British Virgin Islands. It’s picturesque and life is laid-back, but few people she meets plan to stick around for more than a week. “Every day is a summer fling down here, and it’s not as great as that sounds,” the 34-year-old writer and PR professional says. Vacationers are often “deliberately looking for a fling,” she says, and that annoys her because, at this stage, she wants more. “Get out of my face,” she thinks to herself upon meeting a cute stranger. “I know what you’re looking for.”

Adeela Abbasi, a 41-year-old in Washington who calls herself a serial monogamist, has never had a summer fling but is wary of them anyway. She calls them “make-believe relationships” or “seasonal one-night stands.” If she were to meet someone who’s just in town for a little while, she’d prefer to be friends rather than get her heart entangled.

Aaron Myers, who’s 35, agrees. “Summer flings are as temperamental as the weather,” he says. Anyone can be having a hot girl (or guy) summer, he says, using the living-it-up catchphrase coined by rapper Megan Thee Stallion. True comfort, he says, “you find in someone who lasts for longer than a moment.” All of his loves, Myers says, have come in the winter, when he finds together time to be more intimate — cuddling up in front of the fire or while waiting out a snowstorm rather than running from the beach to an outdoor concert to a rooftop bar.

“In fall and winter, you know who a person really is,” he says. “In summer, you get to know who a person wants to be.”

It is possible to find a fling that lasts. At the bar in Adams Morgan, just a few tables from Freed and Raps is Jesse Crane, a 25-year-old woman standing with a man who was supposed to be just a Memorial Day weekend thing two years ago. Tonight, they’re celebrating their engagement.

Months after Raps’s summer fling strayed before her eyes, he called her to apologize. “I was probably a rebound,” she says of their time together. A rebound may be the only acceptable way to have a meaningless summer fling, she says.

But how often are two people both looking for a rebound at the same time? Now that’s a boardwalk game with tough odds.