This study evaluates the predictive skill of the downscaled German Climate Forecast System Version 2.1 (GCFS2.1) for warm spells in Germany on a seasonal scale for both warm (spring and summer) and cold seasons (autumn and winter). The analysis considers hindcast data from the 1991–2020 base period, statistically downscaled to a high spatial resolution over a region including Germany, along with five climate indices (Summer Da...