What is the biggest difference between the record high and record low on a single day in Chicago?

Dear Tom,

What is the biggest difference between the record high and record low on a single day in Chicago?

Thanks,
Jerry Ruzicka
Warrenville

Dear Jerry

Chicago’s vigorous continental climate, from the moderating influence of the oceans, allows it to experience large daily and seasonal temperature fluctuations. The records show that on any given day, winter or summer, Chicago has been both surprisingly warm and cold. The city’s extremes on July 24, for example, are a high of 105 degrees in 1934 and a low of 53 degrees in 2000, a range of 52 degrees, but the largest of all occurred on January 20, a span of 90 degrees between the record high of 63 in 1906 to the city’s all-time record low of minus 27 in 1985. A close runner-up is January 25 with an 87-degree span between the 67-degree high in 1950 and the low of minus 20 in 1897.