What were the dates of the first and last measurable snowfalls in the past three winters?

Dear Tom,
Please settle a dispute between two stubborn friends. What were the dates of the first and last measurable snowfalls in the past three winters?
— M. Tasmin Thoren
Dear M.,
Despite the fact that we’ve just passed the autumnal equinox, we are rapidly approaching the earliest dates for the start of a Chicago snow season. While the city has recorded a trace of snow as early as Sept. 25 in two years — 1928 and 1942 — the city’s earliest measurable snowfall (0.1 inches-plus) occurred Oct. 12, 2006, when 0.3 inches fell. The city’s latest trace of snow was observed on June 2, 1910, and the latest date for measurable snow was 0.2 inches on May 11, 1966. The first and last measurable snowfall dates for the past three snow seasons: 2015-16 Nov. 20-April 8; 2016-17 Dec. 4-March 14; and 2017-18 Nov. 10-April 19.