Arnhem's winters are cold and unpredictable, with temperatures often dropping below freezing point in January and February, but can rise to mild highs. Spring is a slow warming period, with March and April temperatures gradually increasing towards average highs around 20°C. Summer brings warm days, especially in June and July, when temperatures frequently reach the mid-20s to early 30s Celsius, although cooler nights are not uncommon. Autumn is similarly mild, with September and October experiencing pleasant temperatures before cooling off again in November and December.