Illinois State Water Survey - University of Illinois at Urbana-Champaign

State Climatologist Office for Illinois

Illinois Climate Normals (updated to 1981-2010)

Jim Angel, state climatologist

Here are the new 1981-2010 climate normals for Illinois locations. Stations are chosen based on length of record and completeness of data. Products covered here are monthly and annual high, low, and mean temperatures, heating and cooling degree days, precipitation, and snowfall.

This map was created in Google Maps so you can pan and zoom (upper left hand corner). Click on a marker to get the location, then follow the link in the phrase "Report for ___". The normals report will pop up in a new window or tab, depending on your browser. If you click on the link below the map, it takes you to a larger map where you can see the stations list on the left hand side.

View Climate Normals for Illinois (1981-2010) in a larger map

The data used in these products come from the National Weather Service (NWS) Cooperative Observer Program (COOP). Most of these sites are from a network of volunteer observers nationwide, using approved instruments and observing techniques to provide high-quality climate data to the nation. The data are archived at the National Climatic Data Center (NCDC).