Are aircraft cabins getting warmer or cooler? Experts blow hot and cold on the subject

You are about to board a long-haul flight at one of the Gulf’s main aviation hubs , where the outside temperature is seasonably warm. The average temperature in your destination city on another continent is a few degrees cooler but would still be classified as a very pleasant late summer day. You and dozens of other passengers have cleared final security checks at the gate and are winding your way along the air bridge towards the cabin doors. Just then you notice more than one passenger wearing a woolly hat. There’s one, there’s another … and now that you are paying attention, there is a passenger wearing a chunky hoodie here and a quilted gilet there among those planning to board. You check your weather app to see if you are missing something, but the forecast shows no sign of dramatic change in either your departure city or your destination. You scratch your hatless head. Hasn’t the plane you are about to board been sat at a warm airport waiting for passengers to board? Wasn’t this the summer that’s been punctuated by well-trafficked global news stories of “oppressive heat and broiling airplane cabins”, according to The New York Times , and the “misery” of sweltering planes, as reported in Politico . But when you do get on the plane, there is nothing exceptional about the cabin temperature, neither boiling nor breezy, although a cold front will blow in steadily over the next few hours as the flight barrels across the Atlantic. The woolly hat and gilet brigade end up being sat in comfort , while you spend the overnight hours scrambling for succour and comfort from an inflight blanket. So, do we now live in a world where aircraft cabins are either too hot or too cold? Several experts say it’s too hard to tell. Deena Kamel, The National ’s aviation correspondent, says there are simply no straightforward answers to the hot or cold question. Anecdotally, she thinks that cabins are colder than they used to be, although given that every human is different, their experiences may vary, too, she says. A group of academics concur. The five authors of the 2024 report titled “A Review of In-Flight Thermal Comfort and Air Quality Status in Civil Aircraft Cabin Environments” published in the Buildings journal, analysed readings from several aircraft types and more than 250 flights to calculate mean cabin temperatures ranging from 22°C to 25.5°C. The authors found that 60 per cent of flights across all aircraft types have cabin temperatures in the range of 23°C to 24°C – which is neither hot nor cold. There is no dominant temperature narrative there, either. But here is the kicker. “It is worth noting that the thermal sensation of passengers is not uniform, and for existing cabin air conditioning systems, the air supply vents located above the passenger’s head result in a colder sensation,” the study found. “Passengers are [also] more sensitive to the thermal comfort of the cabin environment because of the lower thermal resistance of their clothing when they fly in summer.” They also found that variations in the cabin environment pressure, light and noise could have an impact on passenger perceptions about temperature. If someone is unwell on the flight in a seat near you, or if you have a moderately disruptive neighbour while you are up in the air, this may cause you to notice or exaggerate other factors that irritate you, such as that too hot or far too cold temperature. The report recommended “to regulate the temperature between 25°C and 27°C for summer and 22°C to 27°C for winter” on flights. Airbus A350s, the type of plane I flew on, are reported to have a default climate setting of about 22°C for its multiple cabin temperature zones, which is not cold enough to necessitate the deployment of winter coats and woollen sweaters nor hot enough to regarded as “oppressive heat”. Another older academic study titled “Fainting Passengers: The Role of Cabin Environment”, which used data from more than 1,000 long-haul flights, found that there was evidence that both cabin pressure and temperature could contribute to the likelihood of some passengers fainting in-flight and that higher cabin temperature might “further trigger this reaction”, which may provide a partial explanation for some flights being run cold. This research, published in 2008, also noted that the environment high up in the sky is “hostile to life” and that outside temperatures can decline to minus-50 degrees and below. That fact seems like a powerful impediment to a warm front sweeping in as one swooshes across the Atlantic. An industry worker also provided some further context for this column. That person described aircraft cabins as dynamic environments and that it’s sometimes hard to find the balance between too hot on the ground and too cold in the air, especially, perhaps, when the departure point is from a humid late summer day in the Gulf. In terms of well-being, my colleague Deena says, cooler cabin temperatures help when it comes to preventing motion sickness and to keep at bay some of the unpleasant odours that are part and parcel of flying long distances in relatively small spaces with lots of other people. So, next time you want to vent about cabin temperatures, remember that the vents themselves may hold all the answers.