What is the ICAO Temperature lapse rate?

The ICAO temperature lapse rate is defined as the rate at which temperature decreases with an increase in altitude in the troposphere. The standard lapse rate recognized by the International Civil Aviation Organization (ICAO) is 6.5 degrees Celsius per kilometer, which converts to approximately 3.5 degrees Fahrenheit per 1,000 feet. This rate is essential for pilots and other aviation professionals as it helps in understanding how temperature changes with altitude can affect aircraft performance and weather phenomena.

Understanding this lapse rate is crucial, especially when planning flights, as it assists in altitude adjustments and optimizing fuel efficiency while also avoiding potential adverse weather conditions associated with temperature variations. Maintaining awareness of the lapse rate can help in flight training and operational safety in various conditions, thereby ensuring better decision-making regarding altitude changes.