Temperature at Altitude Calculator
Assume −6.5°C per km (ISA) up to 11 km
Default 15°C (ISA)
How to Use This Calculator
1
Enter Altitude
Height above sea level, in meters.
2
Optionally set Sea-level Temperature
Use 15°C for ISA, or customize for local conditions.
3
Calculate
Result shows estimated outside air temperature.
Formula
T(h) = T₀ − L · h
L = 6.5 K/km = 0.0065 K/m, h in meters
Note: Valid in troposphere under ISA.
About Lapse Rate
The standard atmosphere assumes a linear temperature decrease with altitude up to the tropopause (~11 km). Real conditions vary with weather.
Frequently Asked Questions
What if the lapse rate is different?
This calculator uses ISA −6.5°C/km. Inversions or strong convection can deviate.
Can I input feet?
Convert feet to meters: 1 ft ≈ 0.3048 m.