Snow on the first day of spring

Dear Tom,
How many times has Chicago had snow on the first day of spring (March 20 or
21)?
Bill Ooms, Alsip
Dear Bill,
Chicago winters are long enough and harsh enough to make us anxious for
spring, but don't be fooled. The beginning of spring comes so early that it
falls well within Chicago's normal snow season.
For people in the atmospheric sciences, spring (so-called meteorological
spring) begins on March 1. In Chicago, measurable snow has fallen on that
date in 24 of the 124 years since snow records began here in 1885 -- about
one year in five (one in 5.2). The greatest amount: 4.6 inches in 1947.
Astronomical spring, defined as the date of the vernal equinox, occurs on
either March 19, 20 or 21. Measurable snow has occurred here 22 times on the
vernal equinox, or one year in six (one in 5.6, actually). The biggest
storm: 6.0 inches on March 20, 1964.