Lapse Rate is best described as:

• A. The rate of decrease of temperature with height
• B. The rate of decrease of pressure with height
• C. The rate of decrease of humidity with height
• D. The rate of decrease of wind speed with height

Answer: (A)

Lapse rate describes how quickly the air temperature falls as you go higher in the atmosphere. It’s the amount by which temperature decreases per unit of height, such as degrees per kilometer. In practice, different lapse rates are used depending on the situation: the dry adiabatic lapse rate is about 9.8°C per kilometer for rising, unsaturated air; the environmental lapse rate in everyday weather is typically around 6.5°C per kilometer but varies with conditions; and the moist adiabatic lapse rate is slower (roughly 4–7°C per kilometer) when moisture condenses and latent heat is released. The key idea is that lapse rate is a measure of how temperature changes with altitude, not pressure, humidity, or wind. That’s why describing lapse rate as the rate of decrease of temperature with height is the best answer.