What is the approximate temperature lapse rate per 1000 feet in the standard atmosphere?

What is the approximate temperature lapse rate per 1000 feet in the standard atmosphere?

• A. -1.0°F per 1000 ft
• B. -5.0°F per 1000 ft
• C. -3.5°F per 1000 ft
• D. 0.0°F per 1000 ft

Answer: (C)

In the standard atmosphere, air temperature falls with altitude at about 2°C for every 1,000 feet you climb. When you convert that to Fahrenheit, it’s roughly a decrease of 3.5°F per 1,000 feet. So, as you go up 1,000 feet, the temperature is about 3.5 degrees cooler. The other numbers don’t match this widely used standard lapse rate: a smaller drop would understate how quickly it cools with height, zero change would mean no cooling at all, and a larger drop would overstate it. This -3.5°F per 1,000 ft figure is the practical approximation pilots use for planning and performance in the standard atmosphere, though real conditions can vary.

In the standard atmosphere, air temperature falls with altitude at about 2°C for every 1,000 feet you climb. When you convert that to Fahrenheit, it’s roughly a decrease of 3.5°F per 1,000 feet. So, as you go up 1,000 feet, the temperature is about 3.5 degrees cooler. The other numbers don’t match this widely used standard lapse rate: a smaller drop would understate how quickly it cools with height, zero change would mean no cooling at all, and a larger drop would overstate it. This -3.5°F per 1,000 ft figure is the practical approximation pilots use for planning and performance in the standard atmosphere, though real conditions can vary.