Frost dates in Illinois
Across Illinois, the typical last spring frost is around Apr 17 and the first fall frost around Oct 21. Your own dates depend on where you are in the state; find your county below.
Most of the state's last spring frosts fall between Apr 7 and Apr 26, and its first fall frosts between Oct 14 and Oct 29.
These are the dates with a 50% chance of a 32°F frost on or after (spring) or on or before (fall), so plan tender crops a week or two after the spring date and keep row cover handy. For dates at your exact ZIP code, use the zone and frost date lookup; for what to plant when, see the planting guide by frost date.
Hardiness zones in Illinois: zone 5a, zone 5b, zone 6a, zone 6b, zone 7a
Frost dates by county in Illinois
| County | Last spring frost | First fall frost | Growing season |
|---|---|---|---|
| Adams | Apr 14 | Oct 23 | About 192 days |
| Alexander | Apr 3 | Oct 31 | About 211 days |
| Bond | Apr 10 | Oct 24 | About 197 days |
| Boone | Apr 30 | Oct 12 | About 165 days |
| Brown | Apr 18 | Oct 15 | About 180 days |
| Bureau | Apr 24 | Oct 17 | About 176 days |
| Calhoun | Apr 20 | Oct 20 | About 183 days |
| Carroll | May 2 | Oct 7 | About 158 days |
| Cass | Apr 19 | Oct 21 | About 185 days |
| Champaign | Apr 20 | Oct 18 | About 181 days |
| Christian | Apr 14 | Oct 23 | About 192 days |
| Clark | Apr 14 | Oct 20 | About 189 days |
| Clay | Apr 10 | Oct 23 | About 196 days |
| Clinton | Apr 6 | Oct 29 | About 206 days |
| Coles | Apr 15 | Oct 24 | About 192 days |
| Cook | Apr 16 | Oct 28 | About 195 days |
| Crawford | Apr 13 | Oct 22 | About 192 days |
| Cumberland | Apr 14 | Oct 20 | About 189 days |
| De Witt | Apr 20 | Oct 20 | About 183 days |
| DeKalb | Apr 28 | Oct 13 | About 168 days |
| Douglas | Apr 15 | Oct 20 | About 188 days |
| DuPage | Apr 28 | Oct 16 | About 171 days |
| Edgar | Apr 21 | Oct 20 | About 182 days |
| Edwards | Apr 4 | Oct 28 | About 207 days |
| Effingham | Apr 13 | Oct 24 | About 194 days |
| Fayette | Apr 10 | Oct 24 | About 197 days |
| Ford | Apr 23 | Oct 17 | About 177 days |
| Franklin | Apr 4 | Oct 27 | About 206 days |
| Fulton | Apr 17 | Oct 19 | About 185 days |
| Gallatin | Apr 7 | Oct 26 | About 202 days |
| Greene | Apr 13 | Oct 22 | About 192 days |
| Grundy | Apr 27 | Oct 23 | About 179 days |
| Hamilton | Apr 11 | Oct 21 | About 193 days |
| Hancock | Apr 13 | Oct 22 | About 192 days |
| Hardin | Apr 19 | Oct 20 | About 184 days |
| Henderson | Apr 18 | Oct 20 | About 185 days |
| Henry | Apr 24 | Oct 17 | About 176 days |
| Iroquois | Apr 24 | Oct 16 | About 175 days |
| Jackson | Apr 9 | Oct 22 | About 196 days |
| Jasper | Apr 13 | Oct 22 | About 192 days |
| Jefferson | Apr 9 | Oct 24 | About 198 days |
| Jersey | Apr 14 | Oct 19 | About 188 days |
| Jo Daviess | Apr 27 | Oct 9 | About 165 days |
| Johnson | Apr 14 | Oct 21 | About 190 days |
| Kane | Apr 26 | Oct 18 | About 175 days |
| Kankakee | Apr 19 | Oct 24 | About 188 days |
| Kendall | Apr 28 | Oct 23 | About 178 days |
| Knox | Apr 21 | Oct 19 | About 181 days |
| Lake | Apr 29 | Oct 21 | About 175 days |
| LaSalle | Apr 26 | Oct 18 | About 175 days |
| Lawrence | Apr 12 | Oct 25 | About 196 days |
| Lee | Apr 26 | Oct 14 | About 171 days |
| Livingston | Apr 23 | Oct 20 | About 180 days |
| Logan | Apr 20 | Oct 16 | About 179 days |
| Macon | Apr 14 | Oct 24 | About 193 days |
| Macoupin | Apr 14 | Oct 21 | About 190 days |
| Madison | Apr 4 | Nov 5 | About 215 days |
| Marion | Apr 9 | Oct 26 | About 200 days |
| Marshall | Apr 20 | Oct 17 | About 180 days |
| Mason | Apr 17 | Oct 19 | About 185 days |
| Massac | Apr 3 | Oct 30 | About 210 days |
| McDonough | Apr 17 | Oct 22 | About 188 days |
| McHenry | Apr 28 | Oct 13 | About 168 days |
| McLean | Apr 23 | Oct 17 | About 177 days |
| Menard | Apr 13 | Oct 21 | About 191 days |
| Mercer | Apr 22 | Oct 19 | About 180 days |
| Monroe | Apr 9 | Oct 26 | About 200 days |
| Montgomery | Apr 13 | Oct 24 | About 194 days |
| Morgan | Apr 17 | Oct 21 | About 187 days |
| Moultrie | Apr 15 | Oct 22 | About 190 days |
| Ogle | Apr 26 | Oct 13 | About 170 days |
| Peoria | Apr 16 | Oct 23 | About 190 days |
| Perry | Apr 12 | Oct 22 | About 193 days |
| Piatt | Apr 16 | Oct 20 | About 187 days |
| Pike | Apr 14 | Oct 21 | About 190 days |
| Pope | Apr 14 | Oct 21 | About 190 days |
| Pulaski | Apr 3 | Nov 5 | About 216 days |
| Putnam | Apr 18 | Oct 22 | About 187 days |
| Randolph | Apr 12 | Oct 22 | About 193 days |
| Richland | Apr 15 | Oct 23 | About 191 days |
| Rock Island | Apr 18 | Oct 24 | About 189 days |
| Saline | Apr 7 | Oct 26 | About 202 days |
| Sangamon | Apr 14 | Oct 22 | About 191 days |
| Schuyler | Apr 16 | Oct 23 | About 190 days |
| Scott | Apr 18 | Oct 20 | About 185 days |
| Shelby | Apr 15 | Oct 23 | About 191 days |
| St. Clair | Apr 12 | Oct 22 | About 193 days |
| Stark | Apr 24 | Oct 14 | About 173 days |
| Stephenson | Apr 26 | Oct 13 | About 170 days |
| Tazewell | Apr 20 | Oct 18 | About 181 days |
| Union | Apr 8 | Oct 29 | About 204 days |
| Vermilion | Apr 21 | Oct 19 | About 181 days |
| Wabash | Apr 2 | Oct 31 | About 212 days |
| Warren | Apr 22 | Oct 15 | About 176 days |
| Washington | Apr 7 | Oct 26 | About 202 days |
| Wayne | Apr 7 | Oct 26 | About 202 days |
| White | Apr 11 | Oct 25 | About 197 days |
| Whiteside | Apr 26 | Oct 14 | About 171 days |
| Will | Apr 20 | Oct 22 | About 185 days |
| Williamson | Apr 9 | Oct 22 | About 196 days |
| Winnebago | Apr 24 | Oct 17 | About 176 days |
| Woodford | Apr 21 | Oct 17 | About 179 days |
Source: NOAA NCEI U.S. Climate Normals 1991–2020, 50% probability of 32°F, from the weather station nearest each ZIP code; each county shows the middle value across its ZIP codes. Hills, valleys and cities can run a week or more earlier or later.