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
Drought atlases from tree rings Drought atlases from tree rings

  • Years of record

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Tree-ring drought atlases provide a paleoclimate analog to modern drought indices, most commonly the Palmer Drought Severity Index (PDSI).  Produced on a regular lat-…

Main variables and Earth System components

Land Drought
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

N/A

    • Timestep

    • Monthly, Seasonal, Annual

    • Collections

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Palmer Drought Severity Index (PDSI) Palmer Drought Severity Index (PDSI)

  • Years of record

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The Palmer Drought Severity Index (PDSI) uses readily available temperature and precipitation data to estimate relative dryness. It is a standardized index that generally…

Main variables and Earth System components

Land Drought
Standardized Precipitation Index (SPI) Standardized Precipitation Index (SPI)

  • Years of record

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The Standardized Precipitation Index (SPI) is a widely used index to characterize meteorological drought on a range of timescales. On short timescales, the SPI is closely…

Main variables and Earth System components

Atmosphere Precipitation Land Drought

    • Formats

    • N/A

    • Timestep

    • Monthly

    • Domain

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    • Collections

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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
CRU sc-PDSI (self-calibrating PDSI) over Europe & North America CRU sc-PDSI (self-calibrating PDSI) over Europe & North America

  • Years of record

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Maps of the monthly self-calibrating Palmer drought severity index (SCPDSI) have been calculated for the period 1901–2002 for the contiguous United States (20°–50°N and 130…

Main variables and Earth System components

Land Drought

  • Experts contributing reviews

  • N/A
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
Pacific Decadal Oscillation (PDO): Definition and Indices Pacific Decadal Oscillation (PDO): Definition and Indices

  • Years of record

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The Pacific Decadal Oscillation (PDO) is defined by the leading pattern (EOF) of sea surface temperature (SST) anomalies in the North Pacific basin (typically, polewards of…

Main variables and Earth System components

Ocean SST - sea surface temperature
Atlantic Multi-decadal Oscillation (AMO) Atlantic Multi-decadal Oscillation (AMO) and Atlantic Multidecadal Variability (AMV)

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The Atlantic Multi-decadal Oscillation (AMO) has been identified as a coherent mode of natural variability occurring in the North Atlantic Ocean with an estimated period of…

Main variables and Earth System components

Ocean SST - sea surface temperature
FWI p95 in ERAI and CESM1-LE (contributed by Danielle Touma) Canadian Forest Fire Weather Index (FWI)

  • Years of record

  • N/A

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

    • Formats

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    • Timestep

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    • Domain

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    • Collections

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Overview: Climate Indices Overview: Climate Indices

  • Years of record

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A climate index is a simple diagnostic quantity that is used to characterize an aspect of a geophysical system such as a circulation pattern. A variety of methods have been…

Main variables and Earth System components

Atmosphere Ocean

  • Experts contributing reviews

  • N/A