How common is it for us to get snow in October?

Dear Tom,

How common is it for us to get snow in October?

Thanks, 
Jaime Olson
Roselle

Dear Jaime,

Chicago climatologist Frank Wachowski told us it’s more common than you think. He informed us that the city has recorded at least a trace of snow in October in 70 out of the 136 Octobers of record (51%), dating back to 1884, the start of the city’s snowfall climatology. While the vast majority of the occurrences are traces, 15 Octobers have recorded measurable snow, most recently last year when 4.6 inches fell on October 30-31. The city’s current October normal snowfall, based on data from 1991-2010, stands at 0.2 inches. Chicago’s snowiest October was in 1989 when 6.3 inches fell, with last year’s 4.6 inches ranking second. Most October snowfalls come as late-month flurries or on the tail-end of rain events when the precipitation changes to snow before ending.