References

Bibliography and related standards for the ISO Standard Atmosphere models.

About the Standard Atmosphere

The International Standard Atmosphere (ISA) is a static, deterministic model that defines temperature, pressure, density, and viscosity as functions of altitude. It is not a forecast or an average — it is a fixed reference used for:

  • Aircraft performance — ISA conditions define baseline aircraft performance metrics (e.g. service ceiling, takeoff distance).
  • Altimeter calibration — Pressure altimeters are calibrated to ISA pressure values. The difference between ISA and actual temperature determines altimeter error.
  • Scientific research — A common baseline enables reproducible comparison of experimental results across locations and times.
  • Industrial applications — HVAC, chemical processing, and aerospace manufacturing use ISA conditions as design references.

The ISA assumes dry air as a perfect gas, a constant gravitational acceleration, and a fixed atmospheric composition. These simplifications make the model deterministic and reproducible, but mean it does not represent any specific real-world location or weather condition. For observed conditions, see ISO 5878.

Standards Family

Several international standards define atmosphere models that are related to or derived from the ISO Standard Atmosphere.

StandardAltitude RangeRelationship to ISO 2533
ISO 2533:1975-2 km to 32 kmFoundation document
ISO 2533:2026-5 km to 80 kmModern revision
ICAO Doc 7488/3-2 km to 80 kmExtends ISA to 80 km
US Std Atm 1976-2 km to 1,000 kmIdentical to 32 km
WMO-2 km to 32 kmIdentical to ISA
ISO/DIS 58780 to 25 kmCompanion: observed conditions by latitude

Bibliography

ISO 2533:2026 (forthcoming)

2026

International Organization for Standardization

Second edition of Standard Atmosphere. Cancels and replaces ISO 2533:1975 and incorporates Addendum 1, Addendum 2, and errata. Covers -5 km to 80 km, includes hypsometrical tables in hPa, and recalculates all values using modern computational methods with improved accuracy.

Relationship: Current revision — supersedes ISO 2533:1975 and all addenda.
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ISO 2533:1975

1975

International Organization for Standardization

First edition of Standard Atmosphere. Identical with the ICAO and WMO Standard Atmospheres from -2 km to 32 km, extended to 80 km using atmospheric research data. Specifies temperature, pressure, density, and other thermodynamic properties as functions of geometric and geopotential altitude.

Relationship: Original standard — the primary document this site implements.
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ISO 2533:1975/Add 1:1985

1985

International Organization for Standardization

Addendum 1: Hypsometrical tables. Relates geopotential altitude to atmospheric pressure for calibration of aneroid and manometer-type instruments. Covers pressure in hPa (0.01 hPa intervals) and mmHg (0.01 mmHg intervals), plus altitude-to-pressure lookup tables.

Relationship: Supplement to ISO 2533:1975 for instrument calibration.
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ISO 2533:1975/Add 2:1997

1997

International Organization for Standardization

Addendum 2: Extension to -5,000 m and standard atmosphere as a function of altitude in feet. Extends the lower altitude range from -2,000 m to -5,000 m, and provides atmosphere tables in 200 ft and 500 ft steps from -16,500 ft to 262,500 ft.

Relationship: Supplement to ISO 2533:1975 extending range and adding foot-based tables.
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ICAO Doc 7488/3

1993

International Civil Aviation Organization

Manual of the ICAO Standard Atmosphere — extended to 80 kilometres (262,500 feet). Provides the same model as ISO 2533 for the lower atmosphere but extends definitions to higher altitudes.

Relationship: Extends ISA from 32 km to 80 km. Identical to ISO 2533 below 32 km.
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U.S. Standard Atmosphere 1976

1976

NOAA, NASA, USAF

The U.S. Standard Atmosphere, 1976. Joint publication by the National Oceanic and Atmospheric Administration, National Aeronautics and Space Administration, and United States Air Force.

Relationship: Identical to ISA from -2 km to 32 km geopotential. Extends to 1,000 km.
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WMO — Guide to Meteorological Instruments and Methods of Observation (WMO-No. 49)

2018

World Meteorological Organization

The WMO Guide references the Standard Atmosphere for calibration and standardization of meteorological instruments.

Relationship: Adopts ISA from -2 km to 32 km for meteorological applications.
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Smithsonian Meteorological Tables

1951/1968

Smithsonian Institution

Compiled by Robert J. List. Historical reference containing standard atmosphere tables and extensive meteorological data.

Relationship: Predecessor reference work. ISA values are consistent with these tables.

SI Brochure (9th Edition)

2019

Bureau International des Poids et Mesures (BIPM)

The International System of Units (SI). Defines all base units (metre, kilogram, second, kelvin, mole) used in the Standard Atmosphere.

Relationship: Defines the system of units used throughout the ISA standard.
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ISO/DIS 5878

2025

International Organization for Standardization

Reference atmospheres for aerospace use. Provides temperature, pressure, density, wind, and humidity profiles for five latitude zones (15° to 80°N) in seasonal models (January and July). Incorporates previous addenda on wind characteristics and humidity. Includes machine-readable XML electronic inserts.

Relationship: Companion standard — provides observed atmospheric conditions to complement the idealized ISA.
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ISO 5878:1982

1982

International Organization for Standardization

First edition of reference atmospheres for aerospace use. Defines temperature, pressure, and density profiles by latitude zone and season from sea level to 25 km geopotential altitude.

Relationship: Superseded by ISO/DIS 5878.
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ISO 5878:1982/Add 1:1983

1983

International Organization for Standardization

Wind supplement to ISO 5878. Provides zonal and meridional wind component data, scalar mean speeds, and percentile values for four latitude bands, modeled using the circular normal (Rice) distribution.

Relationship: Supplement to ISO 5878:1982 adding wind characteristic data.
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ISO 5878:1982/Add 2:1983

1983

International Organization for Standardization

Humidity supplement to ISO 5878. Provides water vapor pressure and mixing ratio profiles for the same latitude zones and seasonal models.

Relationship: Supplement to ISO 5878:1982 adding humidity profiles.
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UnitsML

2011

UnitsML Group

Units Markup Language. An XML vocabulary for encoding scientific units of measure.

Relationship: Standards-based representation of units used in atmospheric calculations.
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