It’s mid-October and Chicago has yet to log its first sub 60-degree high temperature this fall. How does that stack up to the average?
It’s very late and depending upon how long the upcoming warm spell lasts it could actually threaten the city’s record latest occurrence of October 29, 1963 when the mercury topped out at just 57 degrees. That date is an outlier with the city’s second latest onset of sub-60-degree highs being October 17, 1882 when the high was also 57. Chicago climatologist Frank Wachowski noted that, on average the city experiences its first sub-60-degree day around September 26th. The two earliest sub-60 highs on record occurrences both took place more than a century ago- 58 on August 30, 1915 and 59 degrees on September 3, 1891.