What is the expected outside temperature at 37,000 feet?

At 37,000 feet altitude, the expected outside air temperature is approximately -55 degrees Celsius. This temperature is typical in the troposphere at cruising altitudes for commercial and military aircraft. As altitude increases, the temperature generally decreases at a rate of about 2 degrees Celsius per 1,000 feet, although this can vary based on weather conditions and the specific layer of the atmosphere.

At 37,000 feet, using the standard lapse rate, we can estimate the temperature based on the average sea-level temperature. This standard atmosphere model indicates that temperatures drop significantly with altitude, leading to the expected value being around -55 C when conditions are typical and standard.

This knowledge is critical for pilots and aircrew as it helps them prepare for potential environmental effects on aircraft performance and systems at high altitudes.