Data Guide


Tristan Ballard

Tristan Ballard

Created: Jan 1, 2023 - Updated: Aug 20, 2023

Heatwaves represent an extended period of perilously warm weather at a specific location or region. They are associated with excess mortality and other human health risks, greatly increased electricity demand, agricultural impacts, and disruption to many types of economic activity.


Future Heatwave Days

Metric: Total days in a given year exceeding the historic 98th percentile for temperature.

This indicator utilizes NASA Global Downscaled Daily Projections (GDDP) to estimate the number of days exceeding the historic 98th percentile of annual temperatures at an asset location. This temperature threshold varies spatially, based on the 98th percentile of a given location during the years 1980 to 2010. As such, the heatwave metric indicates anomalously high temperatures relative to each location’s historical temperature distribution.

Observed Heatwave Days This indicator presents the same heatwave metric as the future heatwave product but instead is based on observed temperature data from the European Centre for Medium-Range Weather Forecasts’s ERA5-Land datasets.

Known Limitations

  • There are many ways to define a heatwave, based on intensity, duration, and potentially other factors. Our indicator uses a 98th percentile intensity, and a 1 day duration, which is appropriate for most use cases.
  • SSP1 is currently not available from the underlying data product, and our product is using SSP2 in place of SSP1 (SSP2 is duplicated in this product).

Sample Assessment

United States Counties

Projected mean annual heatwaves risk exposure over 2022-2052 with the SSP5-RCP8.5 scenario.

US Counties with top cyclone exposure over 2022-2052        
State County Name Score (1980-2020) Score (2022-2052) Percent Change
Florida Miami-Dade 0.69 38.12 450
Idaho Cassia 7.88 34.18 333
Utah Summit 8.11 34.13 326
Utah Morgan 8.1 34.08 321
Utah Box Elder 8.04 33.72 319

Indian Towns

Projected mean annual heatwaves risk exposure over 2022-2052 with the SSP5-RCP8.5 scenario.

Indian Towns with top heatwave exposure over 2022-2052      
Region Name Score (1980-2020) Score (2022-2052) Percent Change
Jaipur 7.85 21.3 172
Lakshwadeep 8.2 90.8 997
Nagpur 7.85 21.51 174
Sikar 7.8 21.2 173
Tonk 7.8 21.65 178

Data Sources

Sea Level Rise