Winters in San Sebastian de los Reyes are cold and rainy, with temperatures often below freezing from January to March. Spring brings mild temperatures, gradually warming up to average highs of around 20°C by May. Summers are warm to hot, with average high temperatures above 30°C from June to August, although occasional cooler days can occur. Autumn is characterized by a cooling trend, with temperatures dropping back down to averages around 10-15°C by October and November. Throughout the year, temperatures rarely drop below -5°C or rise above 40°C.