Also... in case this bleeds over into November 1. From 1990 onward, only 2 Novembers have produced measurable snow in the first 7 days of the month... 1993 (0.1"), 1997 (0.3").
So to summarize... from 1990 onward, there have been 5 different years with measurable snow at ORD between October 1 and November 7. 1992, 1993, 1997, 2006, 2014. But only 3 years when restricting to October -- 1992, 2006, 2014.