The Extreme Cold Outside an Airplane: Understanding Altitude and Temperature Variations

The temperature outside an airplane at cruising altitude is a topic often of great curiosity, especially to those who fly frequently. At cruising altitudes typically around 30,000 to 40,000 feet, the temperature can drop drastically, often ranging from -40°F to -70°F or -40°C to -57°C. This temperature can vary based on the altitude, geographic location, and weather conditions. At these high altitudes, the air is much thinner, contributing to the lower temperatures.

Temperature at Cruising Altitude

The temperature outside an airplane at cruising altitude is typically very cold, often around -40°C (-40°F) or even colder. This phenomenon is due to the significant decrease in air pressure and density as you ascend to high altitudes. The temperature drops approximately 2°C (35.6°F) for every 1,000 meters (3,280 feet) of altitude gained. Therefore, a commercial airplane flying at a typical cruising altitude of 10,000 meters (32,800 feet) would experience temperatures around -50°C (-58°F).

Factors Influencing Temperature

It's important to note that the temperature outside an airplane can vary based on several factors, including the specific altitude, geographic location, and local weather conditions. Additionally, the temperature at cruising altitudes is significantly lower than at sea level due to the drop in atmospheric pressure and density. To give a specific example, at 36,000 feet, the standard temperature is around -13°C (-67°F).

The key factors influencing temperature include:

The altitude at which the airplane is flying The geographic location of the airplane The time of year and seasonal changes The jet stream and its effects Weather patterns and atmospheric conditions

Effect on Passenger Comfort

This extreme cold outside the aircraft is why pressurized cabins and heating systems are essential for passenger comfort and safety on commercial flights. The cabin is typically maintained at a comfortable temperature, often around 20-25°C (68-77°F), to protect passengers and crew from the freezing conditions just beyond the fuselage. Without this controlled environment, passengers would experience extreme discomfort and potential health risks.

Temperature at Different Phases of Flight

It's worth noting that the temperature of the air outside an airplane can vary depending on the phase of the flight. For instance, when an airplane is sitting on the runway, the temperature outside the airplane is the same as the rest of the city it's in. This temperature can be significantly different from the cold temperatures experienced at high altitudes.

As a general rule of thumb, the air temperature drops by 6 degrees Celsius for every 1,000 meters of height you gain. If an airplane is flying at 30,000 feet and the ground temperature at the airport is 20 degrees Celsius, the outside temperature at 30,000 feet would be around -45°C (-49°F) or lower.

These temperature variations are a crucial consideration for pilots and manufacturers when designing and operating aircraft to ensure passenger safety and comfort.

In conclusion, the temperature outside an airplane at cruising altitude is a significant factor due to the effects of altitude on air pressure and density. Understanding these factors is essential for anyone interested in aviation or human comfort at high altitudes.