Temperature by Altitude Calculator

Estimate how much colder it is up a mountain or at flight altitude. Enter the temperature and altitude where you are and the altitude you want.

How to use the Temperature by Altitude Calculator

Enter the temperature at your starting point.
Enter the starting and target altitudes.
Choose a lapse rate (standard is fine for most uses).

How it works

In the lower atmosphere, temperature usually falls with height. The standard lapse rate is 6.5 °C per 1,000 m (about 3.6 °F per 1,000 ft). Dry, rising air cools faster — about 9.8 °C/km — while cloudy, saturated air cools more slowly, around 5 °C/km, because condensation releases heat. Temperature inversions, common on calm, clear nights and in valleys, can reverse this.

Temperature drop with altitude (standard rate)

Altitude gain	°C cooler	°F cooler
1,000 ft	2	3.6
3,000 ft	5.9	10.7
5,000 ft	9.9	17.8
10,000 ft	19.8	35.7
14,000 ft	27.7	49.9
20,000 ft	39.6	71.3
30,000 ft	59.4	107

Frequently asked questions

How much colder is it per 1,000 feet?

About 3.6 °F (2 °C) on average; up to 5.4 °F in dry air.

How cold is it at 35,000 feet?

About −54 °C (−65 °F) in the standard atmosphere.

Why is it colder on mountains?

Air expands and cools as it rises because pressure is lower at altitude.

What is a temperature inversion?

A layer where temperature increases with height, trapping cold air and pollution near the ground.