Summer is finally here, with hot, humid days that will tempt many men to ask themselves: Should I take my shirt off?

"It's a really interesting etiquette question," said Daniel Post Senning, great-great-grandson of famed etiquette expert and an author, speaker and podcaster with the Vermont-based Emily Post Institute.

Until the 1930s, it was illegal in most cities and states in America for men to go shirtless in public, according to the Washington Post. And while male shirtlessness is "not verboten" because it's no longer considered "explicitly revealing," it is "incredibly casual," Senning said.

But etiquette is about the impact you have on other people, said Juliet Mitchell, a Twin Cities-based etiquette expert. So even though you might be comfortable in your own skin, people around you might not be.

"We as a people, especially here in America, we lean toward public modesty," Mitchell said. "You're revealing too much, and it's not tasteful for all age groups."

That's why Darwin Beyer keeps his shirt on in public. Beyer is president of the Oakwood Club, a nudist campground near Stacy, Minn. Still, when he's out and about in his hometown of Wanamingo, Minn., he wears a shirt.

"You just don't do it," he said of going shirtless. "It's not socially acceptable."

So when is going shirt-free socially acceptable? We asked a few experts where and when it's OK for men to bare their torsos. Here's what they said:

At a beach, pool or boat

Taking your shirt off at the beach or the pool is fine, because you might be taking a dip. You can feel fine taking off your shirt on a friend's boat, but maybe not at a backyard barbecue.

Still, just being near the water might not be good enough for some. A columnist for the Daily Mail ripped into TV personality Simon Cowell for going shirtless while walking along the quayside in Nice, France.

"Topless! Topless in a public place that happens to be neither a beach nor a swimming pool, nor the changing room at Helmut Lang," the British tabloid gasped.

Working out

It's pretty common for male runners to exercise without a shirt on to try to stay cool in warm weather.

"The exertion provides a context for someone understanding why your shirt might be off," Senning said.

"I don't have an issue with it," said Jeff Metzdorff, owner of the Mill City Running store in Minneapolis and the Saint City Running store in St. Paul. "If you're confident and you want to get out there and run shirtless, by all means. It's a runner norm," Metzdorff said. "It comes with the territory of being with a runner."

But even dedicated runners try to minimize their exposure to non-runners.

"When it's really hot outside I'll go shirtless because I see no point in putting on a shirt just to get it all sweaty within two minutes," said Todd Millenacker, an ultradistance runner from Savage. "That said, I don't stop and talk to neighbors when I'm running shirtless because it does feel awkward, and you never quite know what they're thinking."

Daniel Barber has run shirtless outdoors — even in temperatures below freezing. But it's easier to do when running in a big city like Minneapolis, where encounters with others are typically anonymous. He's more likely to wear a shirt in his small town of Granite Falls, Minn., because there's a lot better chance that he'll run into someone he knows.

"It's a respect thing," he said.

When you're running shirtless outdoors, spectators will only see you for a moment. That's not the case if you're exercising in a gym, which is why places like the YMCA and Life Time have "appropriate attire" policies that mean men generally have to wear shirts while working out.

If you're not vigorously exercising, just going for a walk without a shirt on like Simon Cowell, you might be viewed less favorably — not as someone trying to stay cool, but as someone trying to be cool.

Interestingly, male shirtlessness on the field is something you won't see much. Under FIFA rules for international soccer, a player will get a yellow card warning if he pulls his shirt off after scoring a goal, a violation of a rule against excessive celebration. And Metzdorff said elite male runners will keep their shirts on even in the hottest weather to keep their sponsors happy.

At sports events

What about going shirtless to watch other people exert themselves?

The exuberant shirtless male fan in the stands is a sporting tradition. Local venues like the University of Minnesota's Huntington Bank Stadium, Minnesota United FC's Allianz Field and the St. Paul Saints' CHS Field don't seem to have policies on male shirtlessness.

Still, Derek Sharrer, general manager of the Saints, said it's not very common at the St. Paul ballfield. "I don't know that we see it that often," he said.

If you're in the mood to watch the game topless, he suggests sitting in the ballpark's grassy berm area, where you can spread out in a picnic-like setting.

Sharrer added that the Saints play a home game on July 14, which happens to be National Nude Day. There will some sort of promotion on that theme, he said. "I don't know how that's going to play out," he said.

At a concert

If you're listening to music and are moved to take off your shirt, read the room, advises Ashley Ryan, vice president for marketing at First Avenue.

The Minneapolis music venue has rules against wearing clothing with hate symbols, but Ryan said there isn't a rule about men going topless. While she's seen shirtless performers and fans at shows, she cautions that it's not appropriate for every performance.

"You'll know if you're in a shirt-off-crowd kind of scene," she said.

At work, on Tinder

Another place where you should think twice before taking off your shirt: online meetings.

Responses were definitely mixed when a Minnesota state senator recently appeared on a Zoom meeting shirtless. Ditto for when a North Oaks City Council member doffed his polo shirt in his hot tub while teleconferencing into a council meeting.

Shirtless photos on dating profiles are also problematic. According to a 2020 study by the Dating.com online dating company, two-thirds of women think a shirtless photo in a man's dating profile is a sign of immaturity, and men with shirtless photos in their profiles have 25% fewer matches.

Similarly, college women who viewed mock Tinder profiles of a young white man considered the man to be less competent, less physically attractive, less socially appealing and more likely to engage in risky sexual behavior if he appeared shirtless, according to a 2022 study by researchers at the University of Colorado and Macalester College.

What about equity?

Finally, if you're thinking about taking your shirt off, at least consider the male privilege behind the act. Women might want to cool off, too, but they don't have the same social freedom to go shirtless.

Some women are fighting for that, however.

In 2019, photographer Michelle Bennett got into an extended debate with a police officer when she went shirtless on Park Point beach in Duluth. And in 2020, the Minneapolis Park and Recreation Board changed its ordinance to no longer make bared "female breasts" in city parks and parkways grounds for an indecent exposure citation.

But the shirt-free debate continues.

"I don't care when a man is topless," Bennett said. But "if women have to keep their shirts on, men do, too."

Memorable shirt-free moments

Throughout history, shirt-free men have been celebrated or greeted with eyerolls. A few notable examples:

"It Happened One Night" (1934): When Clark Gable reveals his bare skin by taking off his dress shirt in this romantic comedy, it supposedly caused such a stir that undershirt sales dropped, though Snopes.com says that might be an urban legend.

"A Streetcar Named Desire" (1951): Before he became the Godfather, Marlon Brando made his mark playing that slice of macho beefcake, Stanley Kowalski, on stage and in the film version of Tennessee Williams' Southern Gothic tale set in a steamy New Orleans. "Hey, you mind if I make myself comfortable?" he says before he strips off a skin-tight, sweat-stained T-shirt under the intense gaze of Vivien Leigh as Blanche DuBois.

"Star Trek" (1966-1969): In this sci-fi TV series, William Shatner so often played Captain Kirk with his uniform shirt torn or completely off that it became a sort of an inside joke for fans. One fan website claims that Shatner appears partially or wholly without his shirt in 25% of the 79 original "Star Trek" episodes.

"Jurassic Park" (1993): Jeff Goldblum reclining shirtless as Dr. Ian Malcolm after a dinosaur attack in this hit movie became such a famous meme that they made a giant statue of it.

Old Spice "The Man Your Man Could Smell Like" commercial (2010): This viral, award-winning commercial featured actor and former pro football player Isaiah Mustafa, shirtless in the shower, then on a boat, then, as he observes, "I'm on a horse." Unlike Vladimir Putin, the image of this shirtless man on a horse was viewed as witty and charming.