The median summertime temperature difference between urban trees and urban fabric is not always consistent with the temperature difference during hot extremes (Fig. 2c and Supplementary Fig. 1). For instance, the temperature differences during hot extremes in Turkey, the Mediterranean, the Iberian Peninsula, France and Eastern Europe are lower than during average summertime conditions, indicating that the cooling provided by trees decreases during hot extremes in these regions. In contrast, in Scandinavia, the British Isles and parts of the Alps/Mid-Europe, the cooling provided during hot extremes is at times even higher than median summertime cooling. The highest cooling is observed to move further north during hot extremes in comparison to average summertime conditions (Supplementary Fig. 17).
The data on LST differences generated in this study have been deposited on zenodo and are publicly available at These data include estimates of the LST differences between urban fabric, urban trees and urban green spaces for each city and the LST differences between urban fabric, rural forests and rural pastures. In addition, estimates of the evapotranspiration of forests and pastures of each city and albedo estimates of urban fabric and forests are provided. All additional data are available from the following sources: Landsat LST can be retrieved from _LandsatLST.html and Aster LST from EU-DEM v.1.0 can be downloaded from -in-situ/eu-dem/eu-dem-v1-0-and-derived-products/eu-dem-v1.0, the Copernicus Urban Atlas and Street tree data from -atlas, E-OBS gridded data from and MODIS albedo and ET data from 2b1af7f3a8