Which days of the year have historically posted the highest and lowest average temperatures?
We passed your question on to Chicago climatologist Frank Wachowski, who quickly provided the answers. When computing the long-term average temperature for every day of the year dating back to 1871, the warmest date is July 27 with an average temperature of 74.9 degrees. Tied for second place are July 17 and 25, each averaging 74.8 degrees. On the cold side of the ledger, the date with the lowest average temperature is February 2, averaging 23.1 degrees, closely followed by February 4 with a 23.2 degree average. Wachowski also provided the city’s absolute warmest and coldest days based on average temperature- July 30, 1916- 93 degrees and December 24, 1983 minus 18 degrees.