Determine the temperature outside of an airplane flying about the earth?

Question

If the temperature of the air at the surface of the earth is 30 C, determine the temperature outside of the airplane flying at 10 kn above the earth.

Answer 1

The temperature drops about 6.5C for every 300 m of elevation gain.

This is an average and varies according to the influence of many factors.

That being said, above about 3300m the temperature is a constant -55C

Answer 2

Actually, the above answer is a bit mixed up.  The typical lapse rate or change in temperature with time is about -6.5C.  But this is for about every 3,300 ft or roughly 1000 m.  



The constant temp of about -55C isn't reached until 11,000 m or about 36,000 ft.