<p>The subject of the study was the characterisation of spatial and multi-year variability in the start and end dates of the thermal growing season and its length in central and northern Europe between 1950 and 2022. Daily mean temperature data, obtained from the European Climate Assessment and Dataset reanalysis collections, were used for the analysis. Based on the above data, the start and end dates, as well as the length of the growing season, were determined. The growing season was defined as the period starting with a 6-day sequence of days with T_mean &gt;5&#xa0;°C after the last spring frost and ending with a 6-day sequence of days with T_mean &lt;5&#xa0;°C after the first autumn frost. The results highlighted a trend toward an earlier start and later end of the growing season, leading to its overall extension across much of the region. Notably, the extension of the growing season was driven more by an earlier start than a later end. These changes were more pronounced in western and northern parts of the study area, offering important insights into the impacts of climate change on seasonal cycles and ecosystems.</p>