Why Airplanes Are Always So Cold & Dry

by SharonKurheg

Hooray, you’re ready for your trip! You’re all packed, and you’ve determined how far in advance you should get to the airport (here’s how to figure it out for your specific circumstances).  You’ve packed your carry on and personal bags so you get through the TSA checkpoint as quickly as possible (Here are some pointers. Don’t forget the 2 TSA rules travelers overlook!). And lo and behold, the flying gods have smiled upon you and your plane takes off on time!

As you’re sitting on the plane, you notice you’re a little chilly. What’s worse, the little old lady next to you (she got stuck in a middle seat. Poor thing) has goosebumps from being so cold.

Of course, this isn’t the first time you’ve been on a plane and felt chilly. And you’re kicking yourself for not packing a light jacket because really, you should know better.

On top of that, in the hour you’ve been on the plane, your skin feels much drier than usual. And, of course, you didn’t pack any lotion in your 1-quart bag-o’-liquids. #travelfail

So why ARE airplanes always so dry? That all has to do with recirculating air. And why are they kept so cold? Believe it or not, the lower temperature is meant to keep you healthy (there’s an actual medical reason behind it).

The dryness

Fun fact! About 50% of the air circulating in the cabin is pulled from the outside. The thing is, the air has practically no moisture at high altitudes. This might cause your throat, nose and skin to feel drier than usual. That’s why you’re always reminded to drink lots of water on a plane – to avoid dehydration.

Besides the lack of humidity on planes, there’s less oxygen inside a plane cabin than on the ground. The air inside an aircraft is usually about 15% oxygen, compared to about 21% oxygen at sea level.

The temperature

Regardless of what the temperature in the cabin is (and we’ll get to that in a second), if the air isn’t humid enough, it makes the air feel colder than it actually is. So that’s part of why it feels chilly – because the humidity level is only about 20% (in a typical home, it’s usually closer to 40-60%).

But beyond that, it’s not just your mind playing tricks on you and thinking it’s colder than it actually is. The temperature on planes IS generally kept lower. That’s to avoid the risk of hypoxia (not having enough oxygen in the body) in passengers and crew members.

A couple of years ago, the ASTM International (American Society for Testing and Materials, an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services) released a study that showed a connection between instances of onboard fainting and cabin temperature. Researchers discovered that the combination of low oxygen levels and warm air increased the risk of fainting. So when passengers were exposed to warm cabin air, on top of those lower oxygen levels, they were more likely to experience hypoxia and faint. So…they keep the cabins cooler.

Anecdotally, lower temperatures may also help prevent motion sickness.

Anyway, planes are typically kept between 71°F and 75°F (22°C and 24°C). That may or may not seem particularly cool to some, but remember that it may feel cooler because of the dryness of the air.

Seats closer to emergency exits may feel a little colder than the rest of the cabin because although these exits are sealed, outside air can still seep into the aircraft.

Who controls the temperature in the plane?

Each airline has its standards for cabin temperatures, and both flight attendants and those in the cockpit have access to controls to raise or lower the temperature.

Feature Photo: Public Domain

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This post first appeared on Your Mileage May Vary

3 comments

RetiredATLATC July 28, 2022 - 6:35 pm

Don’t like dry, but I’ve always found cabins to extremely warm, to almost hot, and makes long flights especially horrible.

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SharonKurheg July 28, 2022 - 6:55 pm

All depends on the person. Joe (hubby) thinks they’re on the warm side too. I think they’re chilly. That’s part of why our blog is called “Your Mileage May Vary” 😉

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Mike R July 28, 2022 - 11:48 pm

The oxygen level inside a plane is not 15%, it’s 21%, like any other air. What’s different is pressurization. The pressure in a plane is like being at 8000 feet up in the mountains. The air is thinner – less pressure – but still contains 21% oxygen. It’s just that there’s less mass of air per beath…

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