Downers Grove's winters are bitterly cold, with temperatures often dropping below freezing and averaging around 0°C in January. Spring brings a gradual warming trend, with March typically being the first month to see average highs reach above 6°C. Summer is warm to hot, with June marking the beginning of a long stretch of high temperatures, peaking in July and August. Autumn cools down rapidly after the sweltering summer months, with September experiencing a noticeable drop in temperature. The coldest months are usually January and February, while the warmest are June through August.