Temperature at altitude calculator
Using this temperature at altitude calculator, you can calculate the approximate temperature at any given altitude using the International Standard Atmosphere (ISA) model.
Temperature at altitude:
15 °C
Related calculators:
How temperature changes with altitude
As you ascend in altitude, the atmospheric temperature decreases at a predictable rate called the lapse rate. The International Standard Atmosphere (ISA) model uses a standard lapse rate of approximately 6.5°C per 1,000 meters (or 3.5°F per 1,000 feet) in the troposphere.
The science behind temperature drop
The temperature decrease occurs because:
- Decreasing air pressure: As altitude increases, atmospheric pressure drops, causing air to expand and cool
- Reduced atmospheric density: Thinner air holds less heat
- Distance from Earth’s surface: The ground absorbs and radiates heat from the sun, warming the air near the surface
International Standard Atmosphere (ISA) Model
The ISA model provides standardized atmospheric conditions used worldwide in aviation, meteorology, and engineering. Key parameters include:
- Sea level temperature: 15°C (59°F)
- Sea level pressure: 1013.25 hPa (29.92 inHg)
- Standard lapse rate: 6.5°C/km (3.5°F/1000ft) up to 11,000 meters.
Practical applications
Aviation
- Flight planning and performance calculations
- Aircraft engine performance optimization
- Fuel consumption estimates
- Cabin pressurization requirements
Mountaineering and hiking
- Gear selection and clothing layers
- Weather prediction and safety planning
- Understanding altitude sickness risks
- Camping equipment temperature ratings
Weather forecasting
- Predicting temperature at different elevations
- Understanding cloud formation levels
- Analyzing atmospheric stability
Engineering and construction
- HVAC system design for high-altitude buildings
- Materials testing under various temperature conditions
- Infrastructure planning in mountainous regions
Important considerations
Limitations of the ISA Model
- Real-world variations: Actual temperatures can vary significantly from ISA predictions due to weather patterns, seasonal changes, and geographical location
- Regional differences: Local climate conditions, latitude, and proximity to water bodies affect actual temperatures
- Seasonal variations: The lapse rate can change with seasons and weather systems
Factors affecting actual temperature
- Time of day: Solar heating affects surface and near-surface temperatures
- Weather systems: High and low-pressure systems alter temperature patterns
- Geographical location: Mountains, valleys, and bodies of water create microclimates
- Humidity levels: Moist air has different temperature characteristics than dry air
Frequently Asked Questions
Why does temperature drop with altitude?
Air pressure decreases with altitude, causing air to expand and cool. Additionally, the atmosphere is primarily heated from below by the Earth’s surface, so temperatures naturally decrease with distance from this heat source.
Is the temperature drop always the same?
No, the standard lapse rate of 6.5°C/km is an average. Actual rates can vary from 4°C/km to 10°C/km depending on atmospheric conditions, humidity, and weather patterns.
At what altitude does temperature stop decreasing?
In the standard atmosphere, temperature stops decreasing at the tropopause (about 11,000 meters or 36,000 feet), where it remains constant at approximately -56.5°C (-69.7°F).
How accurate are these calculations for real-world conditions?
ISA calculations provide a baseline estimate. Actual temperatures can vary by ±10°C or more from ISA predictions due to weather, geography, and seasonal factors. Always check local weather forecasts for accurate conditions.
Historical context
The International Standard Atmosphere was established in 1976 by the International Civil Aviation Organization (ICAO) and has been refined over decades of atmospheric research. It represents average conditions and serves as a universal reference for aviation, meteorology, and engineering applications worldwide.
Tips for using this calculator
- Remember it’s an estimate: Use ISA calculations as a starting point, not absolute truth
- Check local weather: Supplement calculations with current weather forecasts
- Consider seasonal variations: Winter and summer conditions can vary significantly
- Account for time of day: Early morning temperatures may be much colder than afternoon temperatures
- Factor in wind chill: Wind can make temperatures feel much colder than calculated values