Temperature at Altitude Calculator (lapse rate: standard, dry adiabatic or custom)

Understanding the temperature at altitude calculator — concept and principle

Air usually gets colder as you climb. This calculator estimates the temperature at a target altitude from a known temperature at a starting elevation, using the standard-atmosphere lapse rate, the dry adiabatic rate or your own value. Hikers, pilots, drone users and students use it to plan clothing, check performance or understand weather.

With the standard lapse rate, 20 °C at sea level becomes about 0.5 °C at 3,000 m.

How it is calculated

T(h) = T₀ − Γ × (h − h₀) ÷ 1000

T₀ is the temperature (°C) at the starting elevation h₀ (m); h is the target altitude (m).
Γ is the lapse rate in °C per km: 6.49 for the NASA standard-atmosphere model, 9.8 for dry rising air, or a custom value.
The standard-atmosphere temperature at h is 15.04 − 0.00649 × h (valid up to 11,000 m), and the last line shows how far your estimate is from it.
°F = °C × 1.8 + 32.

The principle

The lower atmosphere is heated mainly from below, by the ground that absorbs sunlight. Air that rises meets lower pressure, expands and cools as it does work on its surroundings. For dry air this cooling is about 9.8 °C per km, which equals g divided by the specific heat of air. In clouds, condensing water vapour releases heat, so saturated air cools more slowly. The average profile of the real atmosphere falls in between, which the standard atmosphere models with about 6.5 °C per km up to the top of the troposphere near 11 km.

Worked example

Default inputs: 20 °C at 0 m, target 3,000 m, standard lapse rate 6.49 °C/km.

Height difference = 3,000 − 0 = 3,000 m.
Temperature change = −6.49 × 3.0 = −19.5 °C.
T = 20 − 19.47 = 0.5 °C = 0.53 × 1.8 + 32 = 33 °F.
Standard atmosphere at 3,000 m = 15.04 − 19.47 = −4.4 °C.
Difference from the standard atmosphere = 0.53 − (−4.43) = 5 °C warmer, because the start was 5 °C warmer than standard sea level.

Each point is the calculator re-run with only “Temperature at the starting point (°C)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Temperature at the starting point (°C)	Temperature at the target altitude (°C)
5	-14.5
10	-9.5
15	-4.5
20	0.5
25	5.5
30	10.5
40	20.5

How to read the result

The estimate is most useful for planning, such as how much warmer clothing a summit needs or how cold an aircraft's engine intake air will be. Real days can differ a lot. Temperature inversions, common on clear calm nights and in valleys, make air warmer with height. Sunlit slopes heat the air locally, and weather fronts bring different air masses. Adding wind chill on exposed summits makes it feel colder still.

Common mistakes

Applying the dry adiabatic rate to the average atmosphere; it describes rising parcels, not the typical profile.
Using the formula far above 11 km, where the standard atmosphere stops cooling.
Mixing feet and metres for altitude.
Ignoring that the starting temperature itself changes during the day.

Keep in mind: This is a model, not a forecast. Check a mountain or aviation weather forecast before trips where cold could be dangerous.

Frequently asked questions

How much colder is it per 1,000 m?

On average about 6.5 °C per 1,000 m, but it varies from day to day.

Why does dry air cool faster than cloudy air when it rises?

In clouds, water vapour condenses and releases latent heat, which offsets part of the cooling.

What is a temperature inversion?

A layer where temperature rises with height, often trapping fog or pollution beneath it.

Sources: NASA Glenn Research Center, Beginner's Guide to Aeronautics, "Earth Atmosphere Model – Metric Units"

Checked 9 Nov 2026. NASA Glenn Research Center, Beginner’s Guide to Aeronautics, “Earth Atmosphere Model – Metric Units” (troposphere up to 11,000 m: T = 15.04 − 0.00649 h). Dry adiabatic lapse rate ≈ 9.8 °C/km = g/c_p (standard value).

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