Basel's winters are cold and variable, with temperatures often below freezing in January and February. Spring brings gradual warming, with April and May averaging around 10°C, allowing for blooming flowers and greenery. Summer months of June, July, and August are warm to hot, with average highs often above 20°C, but also experiencing cooler days. Autumn sees a return to more moderate temperatures in September and October, before cooling down again by November and December.