Chicago Snow in May

Dear Tom,
How rare is it for Chicago to receive snow in May?
—Gladys Reynolds
Dear Gladys,
Snow during May in Chicago is not as rare as you might think. The city’s May snow
records date to 1885, and in those 123 Mays, snow has been recorded in 31 of them, a
frequency of once every four years. Of course, the vast majority of those May snows
were insignificant. But over the years the city has experienced a few noteworthy May
snows. In 1940 the city was surprised by a 2.2-inch snowfall on May 1-2 with some
northwest suburbs receiving as much as 5 inches. On May 3, 1907, 1.3 inches of snow
was logged. The city’s latest measurable May snow took place on May 11, 1966, when
0.2 inches fell. Chicago’s most recent encounter with snow in May took place three
years ago, when a trace was reported on May 2, 2005.