A climatological analysis of a 22-year long data set (PANGAEA data repository: doi:10.1594/PANGAEA.919186) was run. Extreme event identification (heatwaves and cold-spells) was performed using the “heatwaveR” package (Schlegel and Smit 2018) in R (R Core Team 2021), which is based on the heatwave definition by Hobday et al. 2016. The longest period with missing data was between May 25th, 1999 and June 16th, 1999. Therefore, the maximum gap length was set to 23 days into the “heatwaveR” package, in which the temperature was linearly extrapolated.