ISWS Bulletin 75, "Precipitation Frequency Study for Illinois" was published in March 2020. This report provides new, updated precipitation frequencies for 10 regions in Illinois for event durations ranging from 5 minutes to 10 days (240 hours) and for recurrence intervals ranging from 2 months to 500 years. New, updated time-distribution characteristics of rainfall events, known as “Huff curves,” are also provided. The precipitation frequency estimates and their time distributions presented in this bulletin supersede those published in Bulletin 70, Circular 172, and Circular 173.