Climatological Heatwave (High Temperature), 1971-2099

Context A climatological heatwave is a prolonged period of extremely high temperature for a particular region that exceeds a maximum threshold. Heatwaves have consequences for health, agriculture, power, wildfire and infrastructure.

Definition The annual number of heatwave days is based on the climatological definition of a heatwave. A climatological heatwave is considered to be a period of at least 3 consecutive days on which the daily maximum temperature exceeds the 99th percentile of the daily maximum temperatures of the May to September season for the control period of 1971 to 2000.

Data Sources The climatological heatwave statistics are calculated using bias-adjusted EURO-CORDEX data for two CMIP5 scenarios with different possible future greenhouse gas emissions: RCP4.5 (medium emissions) and RCP8.5 (high emissions). The data covers the period 1971 to 2099 and statistics are averaged for 30 years in overlapping time periods set 10 years apart. Finally, the time series are averaged for the model ensemble.

Supporting Information The data was collated on behalf of the Copernicus Climate Change Service (C3S). Further information about this index can be found in the C3S documentation resources in the Climate Data Store.

Visualisation and Navigation The map shows the 30-year average of the number of climatological heatwave days for the chosen time period and scenario plotted as area means for each region. The EUROSTAT NUTS classification (Nomenclature of Territorial Units for Statistics) is a hierarchical system for dividing up the economic territory of Europe. The size of the regions shown on the map can be adjusted by selecting the appropriate NUTS level: national level (NUTS-0), first sub-national level (NUTS-1), second sub-national level (NUTS-2), and third sub-national level (NUTS-3).

The regions on the map facilitate dynamic access to the underlying data. Hover the mouse pointer over a region to view the value of the area mean or click on a region to request a time series plot. Likewise, the trans-national average for the EEA member and cooperating countries (EEA 38) can be accessed via the "Europe" bounding box.

The time series plot shows the ensemble mean and standard deviation (SD) of climatological heat wave responses to the chosen scenario conditions across the EURO-CORDEX regional climate model ensemble. The values represent the centres of a 30-year running average from 1971 to 2100 which results in a time series covering the period from 1986 to 2085.

Click and hover the mouse over the time series plot to view the data values and to reveal action buttons for features such as “zoom” and “download plot as a png”. Links below the plot enable the download of time series data in the spreadsheet compatible .csv format.