Too Hot to Fly? Why Climate Change Could Affect Your Flight

Extreme temperatures can ground planes, alter departure times

By Matt Neistein

Published August 15, 2022

Read Time: 4 mins

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When weather disrupts air travel, we typically think of dramatic events: thunderstorms, blizzards, even tornadoes.

But sometimes, it just gets too hot to fly a plane. Literally.

And while those occasions have been few and far between, climate change and increasing temperatures around the globe are bringing more attention to the effect of heat on commercial aviation.

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“The robustness of aircraft and indeed the robustness of the entire aviation system should be monitored carefully, as the sector will have to prepare for the more extreme meteorological conditions that are expected in the future as the climate continues to change,” wrote the International Civil Aviation Organization in a 2016 report.

When record heat in the United Kingdom this summer caused a “surface defect” in a runway at Luton Airport north of London—later clarified as a small part of the runway lifting—it was widely referred to as the runway “melting.”

A Royal Air Force base encountered a similar issue around the same time. Both airports had to suspend or divert flights as a result.

But the effects of extreme heat don’t have to be so dramatic to keep aircraft grounded. While surface temperatures can affect infrastructure like runways, the air temperature alone can prevent an airplane from even taking off.

Physics of flight

Controlled mechanical flight involves an incredible number of factors, but among the most fundamental are two pairs of physical principles: (1) thrust and drag, and (2) lift and mass (or weight).

Put very simply, thrust must be generated by engines to move the aircraft against the opposing drag force, and enough lift must be generated to overcome the mass of the vehicle and achieve liftoff. Every pilot understands how these principles interact and affect an aircraft.

However, one uncontrollable variable is also crucial to this process: air density.

Air is less dense at hotter temperatures which reduces the takeoff performance of aircraft. As a result, flights may have to depart with less passengers on board and in extreme cases, delay flights. (Photo by Beth Hollerich)

Generally speaking, the hotter the air, the lower its density; that is, the molecules comprising it are further apart. Thinner air generates less lift and requires engines to work harder to create thrust.

That’s why, for example, aircraft have specifically assigned limits to how high they can fly based on their size, power and other characteristics. The higher you go, the thinner the air.

But air density, or the lack thereof, can prevent a plane from even getting off the ground, as well.

“With less air density, you’re going to need a greater speed to generate the same amount of lift that you ty