What is the standard temperature lapse rate per 1,000 feet?

The standard temperature lapse rate in the atmosphere is a key concept in understanding how temperature changes with altitude. In the standard atmosphere, the temperature typically decreases by approximately 2°C for every 1,000 feet of ascent. This is termed the "standard lapse rate."

This decrease occurs because, as altitude increases, the atmosphere becomes less dense, and the air retains less thermal energy. Therefore, at around sea level, the average temperature might be higher, and as you climb to, say, 5,000 feet, the temperature would generally be expected to drop by about 10°C (approximately 2°C per 1,000 feet).

Understanding the lapse rate is crucial for pilots, as it affects aircraft performance, weather patterns, and the behavior of air masses. For instance, knowing that the temperature decreases with altitude can help in anticipating changes in aircraft performance and potential weather phenomena, like turbulence.

Thus, the choice indicating a lapse rate of 2°C per 1,000 feet accurately reflects this standard atmospheric condition.