# Temperature at Altitude Calculator

URL: https://speedycalculator.com/calculators/physics/altitude-temperature/
Last updated: 2026-10-30

> The temperature at altitude calculator estimates the air temperature at a given height from the temperature at ground level, using the standard environmental lapse rate of 6.5 °C per km up to the tropopause.

## Inputs

- Temperature at the ground (°C, °F, K)
- Ground elevation (m, ft)
- Target altitude (m, ft, km)

## Results

- Temperature at altitude
- Temperature change

## Formula

```
T(h) = T₀ − 6.5 °C/km × (h − h₀) (up to 11 km),  then constant at T₀ − 71.5 °C
```

## Explanation

Climb a mountain and it gets colder – on average 6.5 °C for every kilometre. Above about 11 km, in the stratosphere, temperature stops falling. That is why airliners cruise in air around −55 °C.

### How to use the Temperature at Altitude Calculator

- **Temperature at the ground**
- **Ground elevation**
- **Target altitude**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Enter the ground temperature, the ground elevation and the target altitude.

### Inputs explained

FieldWhat to enterTemperature at the groundUnits: °C, °F, KGround elevationUnits: m, ftTarget altitudeUnits: m, ft, km

### What each result means

- **Temperature at altitude** = [Temperature at the ground] - 0.0065×(min([Target altitude], 11000) - [Ground elevation])
- **Temperature change** = -0.0065×(min([Target altitude], 11000) - [Ground elevation])

### Example values

How the main result changes when **Temperature at the ground** changes and everything else stays at the example values above:

Temperature at the ground (°C)Temperature at altitude (°C)10-9.515-4.5200.5255.53010.54020.5

## Worked example

Inputs — Temperature at the ground: 20 °C; Ground elevation: 0 m; Target altitude: 3,000 m.

Results — **Temperature at altitude = 0.5 °C**; Temperature change = -19.5 K.

## Key terms

- **Lapse rate**: Rate of temperature decrease with height.

## FAQ

**Why does air cool with height?**
Rising air expands at lower pressure and cools.

**Is the lapse rate always 6.5 °C/km?**
No – it varies; temperature inversions can even reverse it.

**How cold is it at 10 km?**
About −50 °C in the standard atmosphere.

**What is the tropopause?**
The boundary at ~11 km where temperature stops falling.


## Sources

- [U.S. Standard Atmosphere 1976 (NOAA/NASA/USAF)](https://ntrs.nasa.gov/citations/19770009539)
- [NOAA / National Weather Service – Weather calculators](https://www.weather.gov/epz/wxcalc)