Extreme Heat Toolkit

According to the United States Global Change Research Program, heat waves (periods of abnormally hot and/or humid weather lasting a few days to weeks at a time) are occurring more frequently in major cities across the U.S. These events can have detrimental impacts on public health. Urban heat islands play a role in these extreme heat events, as the buildings and impervious surfaces (such as roads and sidewalks) of cities and developed areas tend to retain heat and have higher temperatures than rural areas.

Long-term data records available through NASA's Earth Observing System Data and Information System (EOSDIS) are an invaluable resource in climate research. NASA also provides data on the critical factors of temperature and humidity, as well as landcover and socioeconomic data that can help in understanding the exposure and vulnerabilities of communities to extreme heat events. This toolkit is designed to support research into extreme heat events by providing easy access to data and other resources.

Discover and Visualize Data

Aura Ozone Monitoring Instrument (OMI) Sulfur Dioxide Daily Total Column in Earthdata Search. Earthdata Search is a data discovery and data access application that enables access to NASA Earth Observing System Data and Information System (EOSDIS) Earth science data distributed by EOSDIS Distributed Active Archive Centers (DAACs).


Temperature data are useful for assessing changes in weather and climate patterns that are critical for monitoring and responding to extreme heat events. By calculating the average temperature over a range of time, typically about 30 years, and comparing forecasted high temperatures with this climate data record, it's easy to determine if temperatures are above or below normal for that time period.

Air Surface Temperature

Land Surface Temperature


Data Tutorials/Recipes


Heat-related Socioeconomic Data

Socioeconomic data help assess the exposure and vulnerability of a community to a disaster. Exposure is the presence of people, ecosystems, and infrastructure in places that could be adversely affected; vulnerability is the likelihood of being adversely affected. NASA's home for EOSDIS socioeconomic data is SEDAC, which is hosted by the Center for International Earth Science Information Network at Columbia University.



Data Tutorials/Recipes



Humidity is a measure of the amount of water vapor in the air. When humidity is high, water does not evaporate as easily and it becomes difficult for the body to cool off through sweating. Humidity is an important factor in determining the heat index, which is measure of how hot it feels when relative humidity is factored in with the actual air temperature (relative humidity is a measure of the actual amount of water vapor in the air compared to the total amount of water vapor that can exist in the air at its current temperature). The heat index is used to determine public health warnings for areas experiencing heat waves.

Data Tutorials/Recipes


Land Cover and Vegetation Cover

Land cover plays a key role in controlling the amount of excess heat absorbed or radiated by urban and built-up environments. Urban heat islands occur when cities replace natural land cover with dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat. Trees, green roofs, and vegetation all help reduce urban heat island effects by shading building surfaces, deflecting solar radiation, and releasing moisture into the atmosphere.

Vegetation indices are calculated from the difference between visible and near-infrared light reflected by vegetation. Healthy vegetation absorbs most of the visible light that hits it and reflects a large portion of light in near-infrared wavelengths. Unhealthy, stressed, or sparse vegetation (such as in areas experiencing drought or extreme heat) absorbs more near-infrared light and reflects more light in the visible spectrum. These differences in reflectance can be detected by satellite-borne sensors and can be converted into imagery showing areas of healthy vs. stressed vegetation.

Along with vegetation indices, data from NASA's ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) mission provide detailed measurements of vegetation temperature, which is an indication of plant stress. Plants with sufficient water are able to maintain their temperature; plants that are stressed by insufficient water caused by drought, extreme heat, and other factors show a temperature rise.

Land Cover

Vegetation Cover

Urban Heat Islands (UHI)/Impervious Surfaces


Data Tutorials/Recipes

Last Updated
Feb 10, 2021