Chicago Seasonal temperature break down - The average median temperature March through May is approximately 45°F with highs averaging at 56°F and lows averaging at 37°F. June through August has an approximate average median temperature of 70°F with highs averaging at 79°F, lows typically average at 63°F. Average median temperatures September through November average out at 52°F, high temperatures average out at 61°F and lows average at 45°F.
The average median temperature December through February is approximately 28°F with highs averaging at 37°F, lows average out at 20°F.
The average Chicago annual median temperature averages out at approximately 49°F. The coldest month in Chicago is January with a median temperature of 23°F, the average high for the month of January is 32°F with an average low of 16°F. The hottest month in Chicago is July with an approximate median temperature of 74°F, the average high for the month of July is 84°F with an average low of 67°F.