Dear Tom,
Has it ever snowed in Chicago in July?
—James Smitterhaus, Chicago

Dear James,
In Chicago snowfall records dating from 1885 (the first full year of snowfall observations here) to the present, snow has never fallen in the month of July. Nor has it ever snowed in August. Those are the only totally snow-free months. Traces of snow have occurred in June and September, and snow has fallen here in all other months of the year. In 1928, Chicago recorded a trace of snow on Sept. 25, and a trace also fell on Sept. 25, 1942. In June, a trace of snow was observed on the 2nd in 1910. Snowfall is recorded in tenths of an inch. A trace of snow is defined as a snow amount too small to measure. It occurs when snow does not accumulate either because of high temperatures or a very, very light snow rate.