Understanding the Temperature Outside an Airplane: Altitude and Environmental Factors

The temperature outside an airplane varies significantly with altitude, especially during cruising. At typical cruising altitudes of 30,000 to 40,000 feet (approximately 9,000 to 12,000 meters), the outside temperature can range from around -40° Fahrenheit (-40°C) to -70°F (-57°C). This variation is influenced by several key factors, including altitude, geographical location, and weather conditions.

Factors Affecting Temperature Outside an Airplane

Altitude

The higher you go, the colder it generally gets. This is because air pressure and density decrease significantly at higher altitudes, causing the air to become much cooler. As a result, the temperature drops about 2°C (3.6°F) for every 1,000 meters (3,280 feet) of altitude gained. For example, at a typical cruising altitude of 10,000 meters (32,800 feet), the temperature might be around -50°C (-58°F).

Geographical Location

The temperature outside an airplane can vary based on its geographical location. For instance, airlines flying over the poles or equator may encounter different temperature ranges compared to those flying over mid-latitudes. The poles generally experience lower temperatures, while tropical regions may have more moderate temperatures.

Weather Conditions

Local weather patterns can also influence temperatures at different altitudes. Factors such as jet streams, the time of year, pressure changes, and frontal activities can cause variations in temperature.

Extreme Cold at Cruising Altitude

At cruising altitude, the temperature outside the airplane is typically very cold, often around -40°C (-40°F) or even lower. This extreme cold is due to the significant decrease in air pressure and density at high altitudes, which allows the air to become much cooler. Commercial flights are designed to handle these extreme temperatures, ensuring the safety and comfort of passengers and crew onboard. The pressurized cabin and heating systems play crucial roles in maintaining a comfortable environment for everyone on board.

Temperature at Sea Level and Runway

When an airplane is on the runway, the temperature outside the airplane is the same as the rest of the city it is in. This is because the temperature at sea level is relatively stable and is influenced by local weather conditions, geographical location, and seasonal changes.

Standard Temperature at Higher Altitudes

Standard temperature at sea level is 15°C (59°F). However, it decreases by approximately 2°C (3.6°F) for every 1,000 feet (304.8 meters) of altitude gain up to the tropopause, which is typically around 36,000 feet. Beyond this height, the temperature remains relatively constant. For example, at a typical cruising altitude of 36,000 feet, the temperature would be around -13°C (-20°F).

Despite these extreme temperatures, pressurized cabins and heating systems ensure that passengers and crew experience comfortable conditions. Passengers often enjoy a cabin temperature maintained at around 20-25°C (68-77°F) to protect them from the freezing conditions just beyond the fuselage.