Iowa City's winters are bitterly cold, with temperatures often dropping below -20°C in January and February. As spring arrives in March, temperatures gradually warm up, reaching average highs around 10°C by April. Summer months of June, July, and August are relatively mild, with temperatures rarely dipping below 15°C, but can soar above 35°C on hot days. Autumn brings a return to cooler temperatures, with averages dropping back down to around 5°C by November. Winters then set in once more, with temperatures consistently below freezing from December through February.