This past October 2018 seemed like the coldest October that I can recall. Am I correct?
You are not. It seems that your perception of last month, was greatly influenced by a mid-month cold spell that featured 14 out of 15 days below normal days from October 11-25. What you have forgotten was the month’s warm open with 10 straight above normal days through October 10, punctuated by a very warm October 9 that averaged 23 degrees above normal with a high of 85 and a low of 70. The month actually closed 0.2 degrees above normal and ranks as just the city’s 55th coolest October dating back to 1871. Over Chicago’s 148 Octobers of records, the average temperature has ranged from a very chilly 45.0 degrees in 1926 and 1917 to a balmy 64.3 degrees in 1963.