Home Database Indicators Climatological Heatwave Days
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Climatological Heatwave Days

Background Information

The Climatological Heatwave Days index is relevant to human health, agriculture, energy, wildfire and infrastructure. This Index is part of the Extreme Heat Hazard type of the Heat and Cold category of the classification.

The index counts the number of days in a year within prolonged periods of unusually high temperatures.

The higher/lower the value, the longer/shorter the heatwave.


The count of days under climatological heatwaves conditions (Number of days). A climatological heatwave is a period of at least three consecutive days exceeding the 99th percentile of the daily maximum temperatures of the May to September season during a reference period.

Data Sources

The data was assembled on behalf of the Copernicus Climate Change Service (C3S) based on climate projections hosted on the C3S Climate Data Store (CDS). The Index data is 30-year period statistics based on a set of eight bias-corrected multi-model simulations ensemble from the EURO-CORDEX experiment. These simulations have a spatial resolution of 0.1° x 0.1° and cover scenarios RCP4.5 and RCP8.5. More information about the dataset can be found in the corresponding CDS documentation resources.

Supporting Information

Further information about this application can be found in the Product User Guide (PUG) of the application in the documentation resources of the CDS.

Data download

The aggregated data shown on the map can be downloaded as csv files.

Visualisation and Navigation

The application has an interactive map on the left side with a set of drop down menus to select the regions (NUTS, Transnational regions or Europe Zones), the time span (Year) and the emission scenario (RCP4.5 or RCP8.5). By clicking on the map, a scrolling panel appears on the right side displaying an interactive plot corresponding to spatial and temporal averages over the selected region. Hover over the plot to see the values.

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