Summer means a loosening of rules and norms. Eating with your fingers is suddenly encouraged, near-nakedness is everywhere and a 6am airport pint is unremarkable. It’s a hot, sticky recipe for social chaos and – if you share my view on showing off ungroomed feet – possibly the end times of human civilisation. Here, then, is everything you need to know about summer etiquette.What to wearSt Stephen's Green, Dublin. Photograph: Collins When is it okay for men to go shirtless?Really only by the beach or pool. There is something perhaps stylishly louche “about walking around a seaside town shirtless, but only if you’re abroad and the temperature is hot”, says Zak Maoui, style director of men’s magazine Esquire. “I run topless in London and other cities abroad when it’s super hot; there’s nothing better. If the recent men’s wear shows are anything to go by, going shirtless under a suit may be back in fashion. I still am not sold, personally.”When and where is it okay to be wrapped in a towel?Are you near water? No? Put some clothes on. “I think you need to be on the beach, by the pool, somewhere there is swimming,” says Jo Bryant, training director of etiquette training company The English Manner. Walking a short distance, say from your holiday apartment or campsite to the pool, is acceptable in a towel but nowhere else in public. “Don’t go shopping in a towel and swimming costume.”Are shorts at work acceptable?It depends. “I would not advise shorts for business attire unless the company culture is extremely casual,” says Myka Meier, author of Modern Etiquette Made Easy. This includes smarter tailored and ironed shorts. “If your bosses are doing it, and that’s setting the company culture, then I think it’s okay, but generally speaking, avoid shorts in the office.” Maoui wears shorts at work: “But I work for a men’s fashion magazine. It really depends on your profession. A friend of mine, who works for a bank in Canary Wharf, told me recently that he was laughed at when he asked about wearing shorts.”What about bare shoulders?Again, where do you work? “Maybe if you’re working at Vogue, but if you’re working in finance or law, then that would be a little too sexy,” says Sara Jane Ho, host of the Netflix show Mind Your Manners.Mariah Humbert, an etiquette expert, advises keeping the rest of you more covered up. “Wear a trouser, or a longer skirt or dress. You’re being mindful of how much skin you’re showing as a whole.” Don’t think you can get away with thin straps or swimwear on a work video call. “Even if you’re home and you’re comfortable, you should still be treating the virtual call the way you would treat an in-person meeting, with the same level of professionalism and intention behind your outfit choice,” she says.Are sandals in the office acceptable?“In more professional environments, they wouldn’t be acceptable,” says Laura Akano, an etiquette coach and founder of Polished Manners. If you do go for sandals, go for smart ones, she advises. “Male, female, it doesn’t matter – foot grooming is essential.”If women are wearing sandals, then so can men, says Maoui. “As long as your toes look decent. I have a rule though: if you’re going to get your toes out at work, your legs should be covered. You aren’t at the beach.”Do men still need to remove hats indoors?“Absolutely,” says Grant Harrold, a former butler to King Charles turned author and etiquette trainer. “This goes back to the time when gentlemen always removed their hat out of respect when entering someone’s home. It’s still a rule that I think very much should apply.”But Maoui, who wears a cap around half of the week, disagrees. “This is so outdated,” he says. “I’m not taking it off inside. Who is it offending? I think a cap can help make a suit look less stuffy and, if anything, that makes you seem more inviting.”When should I take off my sunglasses?You should raise them when greeting someone, though Ho says she wouldn’t necessarily do this with a close friend. But for someone you don’t know well, and want to make a good impression on, take off your sunglasses and establish eye contact. “Let’s say we’re together at an event for an extended period of time, it’s sunny and it’s outdoors. At some point I would put them back on,” says Ho. Indoors, you should definitely take them off (as long as you don’t need them for sight-related issues). “There’s nothing more obnoxious than wearing sunglasses indoors,” she adds.Can flip-flops be worn away from the beach or pool?No, says Ho. “They’re just not very presentable, and they’re very teenage. So, how old are you? There’s context for everything. If you’re at a beachside clam hut, flip-flops are great.” There are plenty of more elegant options that are just as wearable away from the pool, she says. “I have a pair of sandals that are a nicer version of Birkenstocks, so they’re easy to put on and they’re casual.” Flip-flops are the shoe of the summer, according to Vogue, but even it acknowledges that it’s the leather or heeled versions that are desirable.Is garden or balcony nudity acceptable?Would you want to see your neighbours naked? You might – or it may provide a helpful reminder to get some chipolatas in for the barbecue tonight – but chances are you’d rather they kept their clothes on. They possibly feel the same about you. If your garden or balcony is visible to others, “it’s not really acceptable”, says Bryant. “If you live in the middle of nowhere, then fine, go for it.”On bodily needsSeapoint near Dún Laoghaire. Photograph: Alan Betson / The Irish Times Is it okay to pee in the sea?“The fish do it, but I would say no,” says Harrold. “A lot of people probably think ‘it’s the open ocean and no one’s ever going to know’, but think of the environment and politeness. Go to the nearest lavatory.”Is deodorant compulsory?“Deodorant is absolutely necessary,” says Humbert. “The way you care for yourself and your hygiene is a form of self-respect, but also respect for the people you work with. It’s the same socially.”Should I tell someone they smell?Yes, almost certainly – it’s the right thing to do, as long as you do it kindly. “If it is at work, try to do it towards the end of the day,” says Elaine Swann, author of Elaine Swann’s Book of Modern Etiquette. That way they won’t spend all day feeling sweaty and paranoid. “Make sure you tell them privately, and give them a way out by saying: ‘I’m not sure if you’re aware of this, but you have an odour that is very prevalent.’”Can I refuse a hug or handshake because I am – or worse, they are – too sweaty?Etiquette, Swann reminds us, “is about putting others at ease, and one way to make someone feel uncomfortable is to give them a handshake or a hug when you’re sweaty”. It’s fine to tell someone you’ll pass on this occasion. “I believe that that is absolutely acceptable, and the individual will appreciate it.” What if it’s the other person who is about to go in for a damp hug or handshake? Swann suggests keeping it light, perhaps suggesting you’re both too hot and offering a quick high five instead. “Adding a bit of levity without putting the person down is acceptable.” But don’t focus on the fact that you have just recoiled from them. “Say it and keep the conversation moving.”Can I borrow sunscreen from a stranger?Ideally not, unless you’ve built up a tiny bit of a relationship with them. “For example, if you’re sitting next to someone at Wimbledon,” says Bryant, “and they’re reapplying their sun cream in the afternoon and you’ve forgotten yours, it would be fine to say, ‘would you mind if I had some?’ But I wouldn’t just go to the park, put my blanket down, walk up to the next group of people and ask to borrow some.” That said, most people react generously. “Once, a stranger came up to me and said their sunscreen had expired and they were burning, and asked if they could have a quick spray for their arms,” says Humbert. “I probably wouldn’t have approached them about it, but I was happy to share.”Is it considerate or overbearing to remind someone to put sunscreen on?It depends on your relationship, and how they take such comments. “I think the right approach would be to put some on yourself and say, ‘would you like some?’ so you’re not judging them. You’re hinting heavily and giving them the opportunity,” says Bryant. If it’s a stranger and you’re anxious that they’re burning, it’s probably best to leave them to it. “As harsh as it may sound, it’s not really your affair.”Can I ask someone else to rub sunscreen on my back?Probably not, unless you know them very well – and even then, there may be numerous other reasons you shouldn’t. “It’s quite an intimate thing to have somebody rub lotion on your body, it should be somebody you are already close with,” says Meier. The social contractClontarf promenade. Photograph: Chris Maddaloni/The Irish Times Is it boring to complain about the heat?It is. “The whole year we complain it’s cold, it’s wet, and as soon as we get heat, we go, ‘it’s too hot,’” says Harrold. (Complain loudly to politicians and fossil fuel investors about the climate crisis instead.)Can I use a fan in public?As long as it doesn’t impact on other people, then yes, says Akano. So a large paper version, possibly not, unless you have a lot of space; a discreet electric fan, probably fine, even on a packed bus. In somewhere like a theatre, “I would say maybe before the production starts, but once it begins, the fan should go off because there will be an element of noise”.How late can I play music or chat loudly in my garden?If you have near neighbours who are likely to be disturbed, then 9pm is about right, says Bryant. “But if you live on a street that’s very communal, and everyone’s out in the evening being noisy, take your cue from them.” If you have children, allowing them to be noisy in the garden on weekend mornings “before 8am is probably unacceptable”.How early is too early to mow the lawn at the weekend?“For that, I’d say a bit later,” says Bryant. No mowing before 9am.Is it acceptable to bring my own speaker to the park or beach?“Turning up to a crowded city park, or busy beach and getting your speaker going super loud is probably going to have a negative impact on other people, so I would say no in that situation,” says Bryant. You could have it on quietly, but this is pointless and irritating. “‘Is it serving its purpose, and who am I disturbing?’ are the two questions you need to ask yourself.”How should fair-weather swimmers/cyclists/tennis players behave in order not to annoy the year-rounders?Oh, you’ve just discovered wild swimming? “Do a little deep dive before you start a summer sport, so that you know you are following the rules,” says Meier. Harrold saw a large number of people at his tennis club discover their inner champion during Wimbledon. If you’re more established, he advises grace towards the newcomers. “Everyone’s got the right to do it. Respect the fact that there’s people wanting to have a go. They’ll probably do it for five minutes, get fed up and move on.”Should I tell a stranger off if they’re walking their dog in the heat of the day?Any responsible dog owner would not be dragging their dog out in the middle of the day, but Harrold – a dog owner – still wouldn’t accost a stranger. “There could be a reason, you don’t know the situation behind it. I’m hoping they will be sensible and stop for rest, water and shade. But if a dog has been left in a car, it’s a different situation.” In that case, assess the dog’s condition and if they’re showing any signs of heatstroke, call 999. However, exercising dogs in hot weather can also be deadly – if you see a dog with obvious and serious overheating symptoms, such as appearing to be in a collapsed state, you can report it to the NSPCA.Eating and drinkingSummer picnics: Bring something home-made, or unopened, and crucially fresh and easy to eat. Photograph: iStock Is it acceptable to start drinking early when at home?“Sunny weather seems to change our behaviour and the social schedule,” says Peyton. “It’s a question of pacing though – if a person drinks beer for breakfast will they peak too early and then not last the day? The good news is that there are many excellent non-alcoholic beer brands which means having the flavour and drinking experience of beer but not the alcohol. Another benefit is that some non-alcoholic beer has isotonic properties which is very useful in blazing heat.”As a guest, how much food should I bring to a summer potluck gathering?Unless otherwise instructed, dishes or items should correlate with adult headcount, says Ho. If you’re arriving with your partner and a friend, and your kids, that’s three dishes, or two plus a bottle of something.As a host, how can I stop someone bringing that revolting dish they always make?Ho advises: “I would say: ‘Oh, instead of bringing that dish I love, we have so many main courses. Can you bring a bottle of wine instead?’”Can I empty my fridge, and bring an opened pot of hummus and half a cucumber to a picnic?If it’s a last-minute thing with friends or family, or where everyone is essentially bringing a packed lunch for themselves, you can probably get away with it, but if it’s for sharing, then sorry, no. Bring something home-made, or unopened, and crucially fresh and easy to eat. And don’t forget serving utensils if the dish needs it. Remember it’s about sharing – don’t keep your food to yourself, even if you’ve brought M&S bits and artisan crisps and everyone else has brought their stale breadsticks from the back of the cupboard. “Just put the food in the middle and at the end of the picnic, if your thing was not eaten, you can take it home with you,” says Meier.Can I ask for ice when ordering a non-ice based drink?Probably, says Peyton. “The customer is always right, so if you want ice in your drink then you can have it, but it will dilute the drink as it melts and that affects the flavour. If the drink is carbonated, for instance beer or cider, ice will make it go flat.” But asking for more ice in a perfectly mixed cocktail is, Peyton warns, “the equivalent of throwing salt on to a Michelin-star chef’s signature dish before tasting it. Don’t do it”.What should I avoid eating in public when it’s hot?“Generally you shouldn’t be walking along the street eating anyway,” Akano reminds us. “But if you’re in a confined space, like the tube or a train or bus, avoid any food with any type of odour.” This is year-round advice, but the heat can exacerbate the smell unbearably. – Guardian