Temperature at Altitude Calculator
Calculate atmospheric temperature changes with altitude using the International Standard Atmosphere model
Calculate Temperature at Altitude
ISA uses standard 15°C at sea level
Altitude for temperature calculation
Atmospheric Layer
Pressure (Est.)
Flight Level
ISA Model Information
Formula Used
ISA Model: T(h) = T₀ + L × (h - h₀)
Where: T₀ = base temperature, L = lapse rate, h = altitude
Troposphere: L = -6.5°C/km (up to 11 km)
Example Calculation
Commercial Flight at Cruising Altitude
Given: Commercial aircraft at 35,000 feet altitude
Standard Conditions: ISA model, 15°C at sea level
Find: Temperature at cruising altitude
ISA Model Solution
1. Convert altitude: 35,000 ft = 10,668 m
2. Identify layer: Troposphere (0-11,000 m)
3. Apply lapse rate: T = 15°C + (-6.5°C/km) × 10.668 km
4. Calculate: T = 15°C - 69.3°C = -54.3°C (-65.7°F)
Result: Typical cruising temperature is around -55°C
Atmospheric Layers
Troposphere (0-11 km)
Temperature decreases -6.5°C/km
Stratosphere (11-47 km)
Temperature increases (ozone layer)
Mesosphere (47-86 km)
Temperature decreases again
Thermosphere (86+ km)
Temperature increases rapidly
ISA Standard Conditions
Sea Level
15°C (59°F), 101.325 kPa
Tropopause
-56.5°C (-69.7°F) at 11 km
Stratopause
-2.5°C (27.5°F) at 47 km
Mesopause
-86°C (-123°F) at 86 km (coldest)
Common Flight Levels
FL100: 10,000 ft (~-5°C)
FL350: 35,000 ft (~-55°C)
Helicopters: 0-20,000 ft
GA Aircraft: 1,000-15,000 ft
Understanding Temperature Changes with Altitude
Why Does Temperature Change?
The atmosphere is not uniform - temperature changes with altitude due to various physical processes. The troposphere is heated from below by Earth's surface, while the stratosphere is heated from above by UV absorption in the ozone layer.
ISA Model Advantages
- •Standardized: Used worldwide for aviation and meteorology
- •Comprehensive: Covers all atmospheric layers up to 86 km
- •Accurate: Based on extensive atmospheric measurements
- •Practical: Essential for aircraft performance calculations
Atmospheric Physics
Each atmospheric layer has distinct characteristics. The troposphere contains most weather phenomena and shows a steady temperature decrease. The stratosphere's temperature inversion is caused by ozone absorbing solar UV radiation.
Key Applications
- •Aviation: Aircraft performance and fuel planning
- •Weather: Atmospheric modeling and forecasting
- •Mountaineering: Cold weather preparation
- •Engineering: High-altitude equipment design
Temperature Lapse Rates
Troposphere: -6.5°C/km
Standard environmental lapse rate
Stratosphere: +1 to +2.8°C/km
Temperature inversion due to ozone
Mesosphere: -2 to -2.8°C/km
Decreasing to -86°C at mesopause
• Adiabatic cooling in rising air
• Radiative heating/cooling
• Atmospheric composition changes
• Radiosondes (weather balloons)
• Satellite remote sensing
• Aircraft-based instruments
• Seasonal changes
• Geographic location
• Weather conditions