Dear Tom,
What date and year has Chicago recorded its earliest measurable snowfall?
John Lustrup
Dear John,
Chicagoans don't think of October as a "snow month," but in fact October brings the
first snow of the approaching winter season in more than half of the years. A computer
scan of the city's official snowfall data set reveals that the first snow of the season has
occurred by Oct. 31st in 65 of 124 years, or 52 percent of the time.
Oct. 12 stands as the date of Chicago's earliest-occurring measurable snow in the
autumn: 0.3 of an inch fell on that date in 2006. However, Chicago weather historian
Frank Wachowski tells us that measurable snow has fallen even earlier in the season at
Midway Airport when 0.2 of an inch fell on Oct. 8, 2000, but Midway was not the official
observation site at that time (by then, O'Hare International Airport was, and still is, the
official site).
