NOAA 1991–2020 freeze normals
Frost Dates in Illinois
Last and first frost at the 145 NOAA stations behind this site's Illinois pages.
At the middle station of the 145 in Illinois where a freeze comes every year, the last spring frost (50%) is April 18 and the first fall frost October 21, a freeze-free season of 185 days. The last frost is earliest at Mount Carmel (Mt Carmel, IL, April 2) and latest at Savanna (Mt Carroll, IL, May 2), 30 days apart. The season runs from 154 days at Savanna to 214 at Granite City.
121 of these stations were also in NOAA's previous normals, for 1981–2010. Between the two, the median station's freeze-free season grew 5 days longer, with the last spring frost 1 day earlier and the first fall frost 4 days later; the season lengthened at 102 stations and shortened at 12. The two periods share twenty years, so the change reflects mostly 2011–2020 against 1981–1990.
Illinois places by frost date
| Place | ZIP | Last frost | First frost | Season | Winters with 32°F |
|---|---|---|---|---|---|
| Chicago | 60629 | April 11 | October 31 | 201 d | 100% |
| Chicago | 60618 | April 10 | November 5 | 208 d | 100% |
| Chicago | 60634 | April 16 | October 28 | 193 d | 100% |
| Waukegan | 60085 | April 30 | October 19 | 170 d | 100% |
| Round Lake Beach | 60073 | April 24 | October 23 | 180 d | 100% |
| Chicago | 60628 | April 10 | November 1 | 203 d | 100% |
| Aurora | 60505 | April 19 | October 23 | 185 d | 100% |
| Mount Prospect | 60056 | April 19 | October 26 | 190 d | 100% |
| Normal | 61761 | April 25 | October 16 | 172 d | 100% |
| Chicago Heights | 60411 | April 23 | October 20 | 179 d | 100% |
| Lombard | 60148 | April 28 | October 16 | 169 d | 100% |
| Bolingbrook | 60440 | April 20 | October 22 | 184 d | 100% |
| Elgin | 60120 | April 26 | October 18 | 174 d | 100% |
| Chicago | 60626 | April 26 | October 21 | 176 d | 100% |
| Joliet | 60435 | April 19 | October 25 | 188 d | 100% |
| Crystal Lake | 60014 | April 25 | October 22 | 179 d | 100% |
| Barrington | 60010 | April 25 | October 19 | 177 d | 100% |
| Lake Zurich | 60047 | April 29 | October 20 | 172 d | 100% |
| Moline | 61265 | April 24 | October 18 | 176 d | 100% |
| Dekalb | 60115 | April 24 | October 18 | 177 d | 100% |
| Carol Stream | 60188 | April 25 | October 19 | 174 d | 100% |
| Bartlett | 60103 | April 30 | October 13 | 163 d | 100% |
| Pekin | 61554 | April 16 | October 23 | 189 d | 100% |
| Orland Park | 60462 | April 19 | October 22 | 183 d | 100% |
| Granite City | 62040 | April 4 | November 5 | 214 d | 100% |
| Springfield | 62704 | April 15 | October 22 | 188 d | 100% |
| Champaign | 61820 | April 15 | October 24 | 190 d | 100% |
| Bloomington | 61701 | April 21 | October 20 | 181 d | 100% |
| O Fallon | 62269 | April 12 | October 20 | 189 d | 100% |
| Belvidere | 61008 | April 28 | October 12 | 166 d | 100% |
| Kankakee | 60901 | April 19 | October 24 | 188 d | 100% |
| Decatur | 62521 | April 14 | October 24 | 192 d | 100% |
| Danville | 61832 | April 21 | October 20 | 181 d | 100% |
| Mchenry | 60050 | May 1 | October 11 | 162 d | 100% |
| Collinsville | 62234 | April 8 | October 26 | 200 d | 100% |
| Quincy | 62301 | April 8 | October 30 | 204 d | 100% |
| Galesburg | 61401 | April 20 | October 19 | 180 d | 100% |
| Zion | 60099 | April 30 | October 21 | 173 d | 100% |
| Rockford | 61108 | April 24 | October 17 | 174 d | 100% |
| Freeport | 61032 | April 26 | October 13 | 169 d | 100% |
| Yorkville | 60560 | April 28 | October 13 | 166 d | 100% |
| Marion | 62959 | April 9 | October 22 | 195 d | 100% |
| Washington | 61571 | April 21 | October 17 | 178 d | 100% |
| Antioch | 60002 | April 23 | October 21 | 179 d | 100% |
| Jacksonville | 62650 | April 17 | October 21 | 186 d | 100% |
| Ottawa | 61350 | April 20 | October 22 | 183 d | 100% |
| East Moline | 61244 | April 16 | October 25 | 190 d | 100% |
| Mount Vernon | 62864 | April 11 | October 22 | 193 d | 100% |
| Dixon | 61021 | April 21 | October 19 | 180 d | 100% |
| Morris | 60450 | April 20 | October 23 | 184 d | 100% |
| Charleston | 61920 | April 15 | October 23 | 187 d | 100% |
| Mattoon | 61938 | April 11 | October 29 | 199 d | 100% |
| Centralia | 62801 | April 9 | October 24 | 196 d | 100% |
| Effingham | 62401 | April 13 | October 24 | 191 d | 100% |
| Quincy | 62305 | April 14 | October 23 | 191 d | 100% |
| Lincoln | 62656 | April 20 | October 16 | 179 d | 100% |
| Streator | 61364 | April 12 | October 28 | 199 d | 100% |
| Macomb | 61455 | April 17 | October 22 | 185 d | 100% |
| Minooka | 60447 | April 16 | October 26 | 191 d | 100% |
| Canton | 61520 | April 17 | October 19 | 185 d | 100% |
| Taylorville | 62568 | April 12 | October 20 | 190 d | 100% |
| Rochelle | 61068 | April 26 | October 13 | 168 d | 100% |
| Mahomet | 61853 | April 23 | October 13 | 170 d | 100% |
| Murphysboro | 62966 | April 9 | October 22 | 195 d | 100% |
| Pontiac | 61764 | April 16 | October 24 | 191 d | 100% |
| Kewanee | 61443 | April 24 | October 17 | 175 d | 100% |
| Rantoul | 61866 | April 21 | October 18 | 179 d | 100% |
| Jerseyville | 62052 | April 14 | October 19 | 187 d | 100% |
| Olney | 62450 | April 15 | October 23 | 189 d | 100% |
| Dunlap | 61525 | April 22 | October 14 | 174 d | 100% |
| Geneseo | 61254 | April 20 | October 20 | 180 d | 100% |
| Harrisburg | 62946 | April 7 | October 26 | 202 d | 100% |
| Benton | 62812 | April 4 | October 28 | 206 d | 100% |
| Paris | 61944 | April 21 | October 20 | 179 d | 100% |
| Salem | 62881 | April 9 | October 26 | 197 d | 100% |
| Poplar Grove | 61065 | April 30 | October 10 | 161 d | 100% |
| Princeton | 61356 | April 22 | October 17 | 177 d | 100% |
| Monmouth | 61462 | April 22 | October 15 | 174 d | 100% |
| Robinson | 62454 | April 13 | October 22 | 190 d | 100% |
| Peru | 61354 | April 24 | October 18 | 176 d | 100% |
| Vandalia | 62471 | April 10 | October 24 | 196 d | 100% |
| Chillicothe | 61523 | April 20 | October 17 | 178 d | 100% |
| Mount Carmel | 62863 | April 2 | October 31 | 209 d | 100% |
| Du Quoin | 62832 | April 6 | October 22 | 199 d | 100% |
| Litchfield | 62056 | April 13 | October 24 | 192 d | 100% |
| Mendota | 61342 | April 27 | October 15 | 171 d | 100% |
| Fairfield | 62837 | April 7 | October 26 | 201 d | 100% |
| Carlinville | 62626 | April 14 | October 21 | 188 d | 100% |
| Sullivan | 61951 | April 15 | October 22 | 187 d | 100% |
| Shelbyville | 62565 | April 10 | October 24 | 195 d | 100% |
| Beardstown | 62618 | April 16 | October 23 | 189 d | 100% |
| Marseilles | 61341 | April 27 | October 17 | 171 d | 100% |
| Anna | 62906 | April 8 | October 29 | 203 d | 100% |
| Lawrenceville | 62439 | April 12 | October 25 | 193 d | 100% |
| Morrison | 61270 | April 26 | October 13 | 167 d | 100% |
| Galena | 61036 | April 26 | October 15 | 170 d | 100% |
| Carmi | 62821 | April 15 | October 19 | 183 d | 100% |
| Pana | 62557 | April 17 | October 23 | 188 d | 100% |
| Oregon | 61061 | April 29 | October 7 | 161 d | 100% |
| Mt Zion | 62549 | April 16 | October 22 | 187 d | 100% |
| Carlyle | 62231 | April 6 | October 29 | 204 d | 100% |
| Vienna | 62995 | April 14 | October 21 | 189 d | 100% |
| Tuscola | 61953 | April 15 | October 20 | 188 d | 100% |
| Flora | 62839 | April 9 | October 24 | 198 d | 100% |
| Petersburg | 62675 | April 13 | October 21 | 189 d | 100% |
| Watseka | 60970 | April 24 | October 16 | 174 d | 100% |
| Saint Joseph | 61873 | April 20 | October 21 | 182 d | 100% |
| Hoopeston | 60942 | April 22 | October 19 | 180 d | 100% |
| Paxton | 60957 | April 23 | October 12 | 170 d | 100% |
| Pittsfield | 62363 | April 14 | October 21 | 189 d | 100% |
| Sparta | 62286 | April 12 | October 22 | 191 d | 100% |
| Sherman | 62684 | April 14 | October 20 | 187 d | 100% |
| Newton | 62448 | April 13 | October 22 | 190 d | 100% |
| Mc Leansboro | 62859 | April 11 | October 21 | 190 d | 100% |
| Auburn | 62615 | April 7 | October 29 | 205 d | 100% |
| Mt Sterling | 62353 | April 18 | October 15 | 179 d | 100% |
| Aledo | 61231 | April 22 | October 19 | 181 d | 100% |
| Nashville | 62263 | April 7 | October 26 | 201 d | 100% |
| Fairbury | 61739 | April 23 | October 15 | 174 d | 100% |
| Dwight | 60420 | April 27 | October 15 | 170 d | 100% |
| Tolono | 61880 | April 19 | October 17 | 180 d | 100% |
| El Paso | 61738 | April 26 | October 17 | 173 d | 100% |
| Casey | 62420 | April 14 | October 20 | 187 d | 100% |
| Gibson City | 60936 | April 21 | October 17 | 178 d | 100% |
| Savanna | 61074 | May 2 | October 7 | 154 d | 100% |
| Knoxville | 61448 | April 21 | October 20 | 181 d | 100% |
| Lena | 61048 | April 27 | October 9 | 165 d | 100% |
| Carthage | 62321 | April 13 | October 22 | 191 d | 100% |
| Athens | 62613 | April 19 | October 19 | 181 d | 100% |
| Carrollton | 62016 | April 13 | October 22 | 190 d | 100% |
| Albion | 62806 | April 4 | October 28 | 206 d | 100% |
| Louisville | 62858 | April 10 | October 23 | 196 d | 100% |
| Neoga | 62447 | April 16 | October 20 | 185 d | 100% |
| Ramsey | 62080 | April 15 | October 19 | 185 d | 100% |
| Galva | 61434 | April 26 | October 12 | 166 d | 100% |
| Winchester | 62694 | April 18 | October 20 | 183 d | 100% |
| Mason City | 62664 | April 17 | October 18 | 182 d | 100% |
| Sesser | 62884 | April 4 | October 27 | 204 d | 100% |
| Camp Point | 62320 | April 18 | October 21 | 187 d | 100% |
| Virginia | 62691 | April 19 | October 17 | 179 d | 100% |
| Colchester | 62326 | April 21 | October 19 | 180 d | 100% |
| Saint Elmo | 62458 | April 3 | October 24 | 202 d | 100% |
| Waterman | 60556 | April 28 | October 10 | 163 d | 100% |
| Granville | 61326 | April 24 | October 17 | 174 d | 100% |
| Walnut | 61376 | April 24 | October 14 | 172 d | 100% |
50% dates from NOAA NCEI U.S. Climate Normals 1991–2020, one row per station; a state page is published when at least 5 stations stand behind its pages. Where a freeze comes in fewer than nine winters in ten, the dates describe the winters that have one.