How rare is freezing rain in April?

Dear Tom,
How rare is freezing rain in April?
— Bruce Becker, Lake County SKYWARN, Libertyville

It is very rare. Glazing from freezing rain was reported throughout the far north and northwest suburbs Sunday morning, with the exception of areas close to the lake. Mundelein observer Phil Rider said the village received one-tenth of an inch of glaze, the first April glazing event in his memory. While the city did not experience freezing rain during the weekend storm, Midway observer Frank Wachowski found that Midway Airport has seen freezing rain only six times in April since 1928, and none since 1957. Wachowski also noted that the latest into April of glazing was on April 9, 1950. Illinois state climatologist Jim Angel provided a seminal study of Illinois winter storms from 1900-1960 by the late Stanley Changnon, that noted only six April glazing events affecting Illinois during that 60-year period.