What is the largest drop in temperatures that Chicago has ever had, from one day to the next?
It was a temperature drop of 61 degrees, from a high of 74 degrees on November 11, 1911, to a low of 13 degrees on the 12th. Mild air covered Chicago on the 11th, but then a chilly blast of Arctic air arrived and the temperature dropped to 32 by midnight and continued downward from there. The high on the 12th was the midnight reading, 32 degrees, but temperatures continued to drop through the day. The temperature hit 13 degrees on midnight at the close of the day on the 12th, eventually falling one more degree, to 12, on the 13th. Heavy rain accompanied the arrival of Arctic air: 1.48 inches fell on the 11th, as well a trace of snow after the cold air arrived. Another trace of snow occurred on 12th.