Climate Indices

Climate indices are simple diagnostic quantities that are used to characterize an aspect of a geophysical system such as a circulation pattern. They track droughts, ENSO events, wind patterns, internal modes of climate variability, and extreme events like wildfires and heatwaves. Climate indices play a key role in climate monitoring and prediction. The climate index overview page summarizes the philosophy of climate indices.

To find a specific climate index, jump to the search box below or click your desired index from among the blue sub-category buttons.

To see only the indices with in-depth commentary, select the "Datasets with guidance" button when using the search box.

Dataset Overviews

Climate datasets

Has expert guidance
U.S. Climate Extremes Index (CEI) U.S. Climate Extremes Index (CEI)

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The U.S. Climate Extremes Index (CEI) was first presented in 1995 as a framework for quantifying observed changes in climate within the contiguous United States. At…

Main variables and Earth System components

Atmosphere Air Temperature Maximum Air Temperature Minimum Air Temperature Precipitation Wind Land Drought
Map of linear trend in R99p https://www.metoffice.gov.uk/hadobs/hadex3/images/HadEX3_R99p_1901-2018_ADW_61-90_1.25x1.875deg_Ann_trend.png HadEX3: Gridded Temperature and Precipitation Climate Extremes Indices (CLIMDEX data)

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HadEX3 provides gridded, station-based indices of temperature- and precipitation- related climate extremes and supersedes HadEX2. It is intended for global and continental…

Main variables and Earth System components

Atmosphere Air Temperature at 2m Maximum Air Temperature Minimum Air Temperature Land Freeze/Thaw
HadEX2: Gridded Temperature and Precipitation Climate Extremes Indices (CLIMDEX data) HadEX2: Gridded Temperature and Precipitation Climate Extremes Indices (CLIMDEX data)

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Note: HadEX2 has been superseded by HadEX3. HadEX2 provides gridded, station-based indices of temperature- and precipitation- related climate extremes. It is intended for…

Main variables and Earth System components

Atmosphere Maximum Air Temperature Minimum Air Temperature Land Freeze/Thaw

  • Experts contributing reviews

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GHCNDEX: Gridded Temperature and Precipitation Climate Extremes Indices (CLIMDEX data) GHCNDEX: Gridded Temperature and Precipitation Climate Extremes Indices (CLIMDEX data)

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GHCNDEX provides gridded, station-based indices of temperature- and precipitation- related climate extremes. It is intended for climate change detection and attribution…

Main variables and Earth System components

Atmosphere Maximum Air Temperature Minimum Air Temperature Land Freeze/Thaw

  • Experts contributing reviews

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NOAA ThreadEx Long-term Station Extremes for America NOAA ThreadEx Long-term Station Extremes for America

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ThreadEx is a data set of extreme daily temperature and precipitation values for 270 locations in the United States. For each day of the year at each station, ThreadEx…

Main variables and Earth System components

Atmosphere Air Temperature Maximum Air Temperature Minimum Air Temperature Precipitation

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FWI p95 in ERAI and CESM1-LE (contributed by Danielle Touma) Canadian Forest Fire Weather Index (FWI)

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Fire weather indices are used to quantify the meteorological conditions that can lead to fire ignition and spread. They are used to communicate fire danger levels to…

Main variables and Earth System components

Atmosphere

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Asymmetry and Diversity in the pattern, amplitude and duration of El Niño and La Niña Asymmetry and Diversity in the pattern, amplitude and duration of El Niño and La Niña

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El Niño and La Niña, the two phases of ENSO, are sometimes described as opposites. However, there are asymmetries in their spatial structure, amplitude, duration and…

Main variables and Earth System components

Ocean SST - sea surface temperature

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Nino SST Indices (Nino 1+2, 3, 3.4, 4; ONI and TNI) Nino SST Indices (Nino 1+2, 3, 3.4, 4; ONI and TNI)

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There are several indices used to monitor the tropical Pacific, all of which are based on sea surface temperature (SST) anomalies averaged across a given region. …

Main variables and Earth System components

Ocean SST - sea surface temperature
Standardized Precipitation Evapotranspiration Index (SPEI) Standardized Precipitation Evapotranspiration Index (SPEI)

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The Standardized Precipitation Evapotranspiration Index (SPEI) is an extension of the widely used Standardized Precipitation Index (SPI). The SPEI is designed to take into…

Main variables and Earth System components

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