Climate Change Indices (ETCCDI)

Figure 1: Climate indices highlight warming trends in Ireland (shown here at Valentia Observatory)

Climate Indices are a useful resource for measuring and quantifying climate variability and associated trends.

The ETCCDI indices are a set of core climate indices, used to monitor the occurrence of climate extremes of temperature and precipitation. The ETCCDI was a UN-backed working group formed to assess the best practices for the characterisation of climate variability and climate change.

These are composed of 27 indices, based on daily observations of temperature and precipitation. All 27 indices are calculated for annual values but a subset of these indices are also calculated on a seasonal and monthly basis.

There are 16 temperature based indices. These primarily focus on both cold and warm extremes of daily minimum temperature (TN) and daily maximum temperature (TX), such as maximum/minimum values, fixed threshold exceedances and also percentile-based thresholds.

The 11 precipitation indices focus on total precipitation accumulations, threshold-based rainfall events and maximum rainfall extremes.

More information on the indices can be found in the tabs below, including factsheets for each individual index.


Date Download
Indices data can be downloaded through the following links:

Annual Seasonal Monthly Station locations