The adiabatic lapse rate is the reason. Its 2°C per 1,000ft or 3.5°F. If the plane is cruising at 30,000ft that’s a temperature difference of 105°F from the plane to the ground.
Did some flying for awhile, gets cold up there.
Edit:
Actually yeah, if the comment above that the plane was 37k-41k is correct. Let’s says 40k for easy math, thats a 140°F temp difference. If the temp at altitude is -52°F then it would be 88°F on the ground. Math checks out!
The adiabatic lapse rate is the reason. Its 2°C per 1,000ft or 3.5°F. If the plane is cruising at 30,000ft that’s a temperature difference of 105°F from the plane to the ground.
Did some flying for awhile, gets cold up there.
Edit: Actually yeah, if the comment above that the plane was 37k-41k is correct. Let’s says 40k for easy math, thats a 140°F temp difference. If the temp at altitude is -52°F then it would be 88°F on the ground. Math checks out!
TLDR shit is cold up there