Most airlines try to keep the cabin near 72°F (about 22°C), a level that balances passenger comfort with the need to counter the -40°C to -55°C skin temperatures found at cruising altitude. Korean Air, for example, publishes a 23-25°C band, while industry data collected by AeroTime Hub show the normal spread is 22-24°C. Because the FAA and DOT impose no operating requirements, the final setting is left to the flight crew, and some carriers have allowed readings as high as 90°F. When ground air-conditioning is weak, the thermometer can climb past 100°F.
Expert behind this article
Jim Goodrich
Jim Goodrich is a pilot, aviation expert and founder of Tsunami Air.
What temperature is an airplane cabin?
In flight, the cabin is normally kept between 22°C (71.6°F) and 24°C (75.2°F), the midpoint of the ASHRAE comfort envelope. If 23°C (73.4°F) is targeted, the incoming conditioned air is typically supplied at 10°C (50°F). These values correspond to room-temperature conditions of roughly 73-77°F (22.8-25°C).
Inside the airplane, crew understand that a comfortable temperature is subjective, so most do their best to keep the thermostat around 70°F (21°C). After takeoff, pilots and flight attendants share control of the system and will target 80°F (27°C) or less. If the cooling does not balance loads, they will fly with a hotter cabin.
Regulatory attention focuses on ground operations: the Association of Flight Attendants has petitioned the U.S. Secretary of Transportation for a federal boarding limit of 80°F (26.7°C), raised to 85°F (29.4°C) if in-flight entertainment screens are switched on. Hawaiian and Spirit instruct agents not to allow passengers to board once the cabin exceeds 85°F (29.4°C). The FAA expects airlines to take action if any ground temperature condition affects passenger safety.
What is the lower limit of air that can be supplied to cabins?
The lower limit at which air can be supplied to the cabin without creating uncomfortable cold drafts is about 10°C (50°F). At a typical cruise altitude of 11,000 m (36,089 ft), the outside air is about -55°C (-67°F), and aircraft exterior surfaces encounter -40 to -55°C (-40°F to -67°F). To prevent this chill from reaching passengers, bleed air passes through air-conditioning units before being distributed throughout the cabin. These units guarantee maximum comfort for all passengers, and all aircraft have systems which remove contaminants and maintain a comfortable temperature. Although the supplied air is cool, the large quantity of outside airflow supplied to the cabin is required to maintain temperature control, and the air on board an aircraft has about 20% humidity.
