freeze | Illinois State Climatologist| Prairie Research Institute

Illinois State Water Survey Illinois State Climatologist

Mild May Wraps Up an Otherwise Warm Spring in Illinois

Published June 7, 2025 by Trent Ford

The preliminary statewide average May temperature was 63.0 degrees, 0.2 degrees below the 1991–2020 average and the 58th warmest on record going back to 1895. The preliminary statewide average total May precipitation was 3.75 inches, 1.02 inches below the 1991–2020 average and the 55th driest on record statewide. Data are provisional and may change […]

Frost in Illinois

Published April 11, 2013 by Jim Angel

For much of Illinois April is typically the last month that we see freezing temperatures until Fall (at least we hope). Below are the maps showing the median dates when we see 28 and 32 degrees for the last time in Spring. The median represents the middle value in the range of dates and is less […]