Naperville experiences a continental climate with cold winters and warm summers. Winters are particularly harsh, with temperatures often below freezing, especially in January and February when lows can drop as low as -22°C. As spring approaches, temperatures gradually rise, with March marking the beginning of milder weather, reaching averages of 6°C. Summer months bring warmth, with June and July averaging highs around 34°C, while September sees a slight cooldown before autumn sets in. Autumn is mild, with October experiencing warm afternoons and crisp mornings, before winter returns with its chill.