Illinois frost dates
Across 170 NOAA climate stations in Illinois, the median last spring frost (32°F) ranges from Apr 2 at Cairo 3N to May 2 at Mt Carroll; the typical station sees its last frost around Apr 18 and its first fall frost around Oct 21.
“Median” dates have a 50% chance of a later spring frost or an earlier fall frost. “10% risk” dates are the safer choice for tender plants: only 1 year in 10 has frost beyond them. Source: NOAA NCEI 1991–2020 Climate Normals. Elevation matters: within a state, frost dates can differ by a month or more between valleys and hills.
| Station | Elevation | Last frost (median) | Last frost (10% risk) | First frost (median) | First frost (10% risk) | Growing season |
|---|---|---|---|---|---|---|
| Albion | 530 ft | Apr 4 | Apr 20 | Oct 28 | Oct 15 | 206 days |
| Aledo | 730 ft | Apr 22 | May 6 | Oct 19 | Oct 6 | 181 days |
| Alton - Melvin Price L&D | 405 ft | Apr 4 | Apr 19 | Nov 5 | Oct 25 | 214 days |
| Altona | 765 ft | Apr 28 | May 12 | Oct 12 | Sep 28 | 165 days |
| Anna 2 Nne | 640 ft | Apr 8 | Apr 26 | Oct 29 | Oct 17 | 203 days |
| Antioch | 750 ft | Apr 23 | May 9 | Oct 21 | Oct 6 | 179 days |
| Athens 4SW | 594 ft | Apr 19 | May 4 | Oct 19 | Oct 5 | 181 days |
| Aurora | 660 ft | Apr 19 | May 4 | Oct 23 | Oct 9 | 185 days |
| Avon | 640 ft | Apr 22 | May 8 | Oct 19 | Oct 5 | 177 days |
| Barrington 3SW | 875 ft | Apr 25 | May 12 | Oct 19 | Oct 5 | 177 days |
| Belleville Siu Rsch | 450 ft | Apr 12 | Apr 28 | Oct 20 | Oct 3 | 189 days |
| Bentley | 650 ft | Apr 13 | Apr 30 | Oct 22 | Oct 8 | 191 days |
| Benton 2 N | 445 ft | Apr 4 | Apr 21 | Oct 28 | Oct 15 | 206 days |
| Bloomington 5W | 852 ft | Apr 21 | May 5 | Oct 20 | Oct 9 | 181 days |
| Brookport Dam 52 | 330 ft | Apr 6 | Apr 23 | Oct 27 | Oct 15 | 203 days |
| Brownstown 4 Sw | 530 ft | Apr 3 | Apr 25 | Oct 24 | Oct 9 | 202 days |
| Cahokia | 400 ft | Apr 6 | Apr 20 | Oct 27 | Oct 14 | 203 days |
| Cahokia St Louis AP | 413 ft | Apr 8 | Apr 23 | Oct 26 | Oct 12 | 200 days |
| Cairo 3N | 313 ft | Apr 2 | Apr 17 | Oct 31 | Oct 18 | 211 days |
| Carbondale Sewage Plt | 390 ft | Apr 9 | Apr 25 | Oct 22 | Oct 10 | 195 days |
| Carbondale Southern Il AP | 406 ft | Apr 9 | Apr 25 | Oct 22 | Oct 8 | 195 days |
| Carlinville | 621 ft | Apr 14 | Apr 30 | Oct 21 | Oct 5 | 188 days |
| Carlyle Rsvr | 501 ft | Apr 6 | Apr 22 | Oct 29 | Oct 16 | 204 days |
| Carmi 3 | 335 ft | Apr 15 | May 2 | Oct 19 | Oct 4 | 183 days |
| Casey | 620 ft | Apr 14 | Apr 30 | Oct 20 | Oct 5 | 187 days |
| Champaign 3S | 721 ft | Apr 15 | Apr 29 | Oct 24 | Oct 11 | 190 days |
| Champaign 9 Sw | 700 ft | Apr 23 | May 9 | Oct 13 | Sep 28 | 170 days |
| Champaign Willard AP | 754 ft | Apr 19 | May 5 | Oct 17 | Oct 3 | 180 days |
| Channahon Dresden Isl Dam | 505 ft | Apr 16 | May 3 | Oct 26 | Oct 13 | 191 days |
| Charleston | 700 ft | Apr 15 | May 3 | Oct 23 | Oct 9 | 187 days |
| Chenoa | 719 ft | Apr 23 | May 7 | Oct 15 | Sep 29 | 174 days |
| Chicago Aurora Muni AP | 710 ft | Apr 28 | May 11 | Oct 13 | Sep 27 | 166 days |
| Chicago Botanic Garden | 630 ft | Apr 26 | May 11 | Oct 21 | Oct 5 | 176 days |
| Chicago Midway AP | 612 ft | Apr 11 | Apr 27 | Oct 31 | Oct 20 | 201 days |
| Chicago Midway AP 3SW | 620 ft | Apr 10 | Apr 26 | Nov 1 | Oct 21 | 203 days |
| Chicago Northerly Is | 583 ft | Apr 10 | Apr 25 | Nov 5 | Oct 24 | 208 days |
| Chicago Ohare Intl AP | 658 ft | Apr 16 | May 1 | Oct 28 | Oct 15 | 193 days |
| Chicago Palwaukee AP | 636 ft | Apr 19 | May 3 | Oct 26 | Oct 13 | 190 days |
| Chicago Waukegan Rgnl AP | 727 ft | Apr 30 | May 16 | Oct 21 | Oct 5 | 173 days |
| Compton 1 Nw | 905 ft | Apr 27 | May 14 | Oct 12 | Sep 27 | 167 days |
| Congerville 2NW | 640 ft | Apr 21 | May 7 | Oct 17 | Oct 3 | 178 days |
| Crystal Lake 4NW | 940 ft | Apr 25 | May 9 | Oct 22 | Oct 7 | 179 days |
| Danville | 555 ft | Apr 21 | May 7 | Oct 20 | Oct 6 | 181 days |
| De Kalb | 873 ft | Apr 24 | May 10 | Oct 18 | Oct 4 | 177 days |
| Decatur AP | 675 ft | Apr 16 | Apr 30 | Oct 22 | Oct 7 | 187 days |
| Decatur Wtp | 639 ft | Apr 14 | May 1 | Oct 24 | Oct 11 | 192 days |
| Dixon 1W | 660 ft | Apr 21 | May 5 | Oct 19 | Oct 4 | 180 days |
| Dixon Springs Agric Ctr | 527 ft | Apr 14 | Apr 30 | Oct 21 | Oct 6 | 189 days |
| Du Quoin 4 Se | 420 ft | Apr 6 | Apr 22 | Oct 22 | Oct 9 | 199 days |
| Dwight | 628 ft | Apr 27 | May 14 | Oct 15 | Sep 30 | 170 days |
| Effingham 3SW | 625 ft | Apr 13 | Apr 29 | Oct 24 | Oct 9 | 191 days |
| Elgin | 763 ft | Apr 26 | May 12 | Oct 18 | Oct 3 | 174 days |
| Elizabeth | 675 ft | May 1 | May 17 | Oct 9 | Sep 25 | 160 days |
| Fairfield Radio Wfiw | 430 ft | Apr 7 | Apr 23 | Oct 26 | Oct 14 | 201 days |
| Flora | 481 ft | Apr 9 | Apr 23 | Oct 24 | Oct 11 | 198 days |
| Flora 5 Nw | 500 ft | Apr 10 | Apr 26 | Oct 23 | Oct 7 | 196 days |
| Freeport Waste Wtp | 750 ft | Apr 26 | May 11 | Oct 13 | Sep 30 | 169 days |
| Fulton L&D #13 | 592 ft | Apr 13 | Apr 28 | Oct 26 | Oct 13 | 195 days |
| Galena | 822 ft | Apr 26 | May 11 | Oct 15 | Oct 1 | 170 days |
| Galesburg | 761 ft | Apr 20 | May 5 | Oct 19 | Oct 4 | 180 days |
| Galva | 810 ft | Apr 26 | May 11 | Oct 12 | Sep 25 | 166 days |
| Geneseo | 639 ft | Apr 20 | May 6 | Oct 20 | Oct 5 | 180 days |
| Gibson City | 750 ft | Apr 21 | May 5 | Oct 17 | Oct 5 | 178 days |
| Gladstone Dam 18 | 538 ft | Apr 8 | Apr 23 | Oct 29 | Oct 17 | 202 days |
| Golden | 718 ft | Apr 18 | May 1 | Oct 21 | Oct 6 | 187 days |
| Grand Chain Dam 53 | 385 ft | Apr 3 | Apr 21 | Nov 5 | Oct 23 | 216 days |
| Grayville | 435 ft | Apr 7 | Apr 23 | Oct 25 | Oct 12 | 201 days |
| Harrisburg | 365 ft | Apr 7 | Apr 25 | Oct 26 | Oct 10 | 202 days |
| Havana | 463 ft | Apr 17 | May 3 | Oct 19 | Oct 1 | 185 days |
| Hennepin | 515 ft | Apr 18 | May 3 | Oct 22 | Oct 7 | 188 days |
| Hennepin Wtr Trmt Plt | 460 ft | Apr 24 | May 10 | Oct 17 | Oct 1 | 174 days |
| Hillsboro | 630 ft | Apr 13 | Apr 28 | Oct 24 | Oct 10 | 192 days |
| Hoopeston | 710 ft | Apr 22 | May 8 | Oct 19 | Oct 5 | 180 days |
| Illinois City Dam 16 | 550 ft | Apr 18 | May 2 | Oct 24 | Oct 11 | 188 days |
| Iuka 12 Sw | 590 ft | Apr 9 | Apr 25 | Oct 24 | Oct 10 | 196 days |
| Jacksonville 2 | 626 ft | Apr 17 | May 1 | Oct 21 | Oct 9 | 186 days |
| Jacksonville 2E | 610 ft | Apr 19 | May 5 | Oct 17 | Oct 1 | 179 days |
| Jerseyville 2 Sw | 630 ft | Apr 14 | Apr 30 | Oct 19 | Oct 7 | 187 days |
| Joliet Brandon Rd Dam | 543 ft | Apr 19 | May 7 | Oct 25 | Oct 12 | 188 days |
| Kankakee Metro Wastewater | 600 ft | Apr 19 | May 3 | Oct 24 | Oct 12 | 188 days |
| Kaskaskia Rvr Navigation Lock | 380 ft | Apr 8 | Apr 25 | Oct 30 | Oct 15 | 202 days |
| Kewanee 1 E | 780 ft | Apr 24 | May 8 | Oct 17 | Oct 3 | 175 days |
| Knoxville | 728 ft | Apr 21 | May 6 | Oct 20 | Oct 7 | 181 days |
| La Harpe | 690 ft | Apr 21 | May 5 | Oct 19 | Oct 4 | 180 days |
| Lacon | 458 ft | Apr 20 | May 7 | Oct 17 | Oct 3 | 178 days |
| Lake Villa 2NE | 840 ft | Apr 24 | May 9 | Oct 23 | Oct 8 | 180 days |
| Lawrenceville 2WSW | 451 ft | Apr 12 | Apr 30 | Oct 25 | Oct 12 | 193 days |
| Lawrenceville Intl AP | 429 ft | Apr 8 | Apr 22 | Oct 26 | Oct 13 | 200 days |
| Lincoln | 583 ft | Apr 20 | May 4 | Oct 16 | Oct 3 | 179 days |
| Lisle-Morton Arboretum | 680 ft | Apr 28 | May 14 | Oct 16 | Oct 1 | 169 days |
| Little Red School Hse | 715 ft | Apr 19 | May 5 | Oct 22 | Oct 8 | 183 days |
| Marengo | 815 ft | Apr 28 | May 14 | Oct 12 | Sep 28 | 166 days |
| Marseilles Lock | 490 ft | Apr 27 | May 13 | Oct 17 | Oct 3 | 171 days |
| Mason City 4SE | 600 ft | Apr 17 | May 4 | Oct 18 | Oct 4 | 182 days |
| Mattoon | 701 ft | Apr 11 | Apr 28 | Oct 29 | Oct 15 | 199 days |
| Mattoon Coles Co AP | 721 ft | Apr 15 | Apr 30 | Oct 24 | Oct 9 | 189 days |
| Mc Henry -Wg Stratton L&D | 736 ft | May 1 | May 19 | Oct 11 | Sep 27 | 162 days |
| Mcleansboro | 446 ft | Apr 11 | Apr 26 | Oct 21 | Oct 6 | 190 days |
| Minonk | 750 ft | Apr 26 | May 10 | Oct 17 | Oct 1 | 173 days |
| Moline Quad City Intl AP | 592 ft | Apr 24 | May 9 | Oct 18 | Oct 4 | 176 days |
| Monmouth | 720 ft | Apr 22 | May 10 | Oct 15 | Sep 29 | 174 days |
| Monmouth 4NW | 724 ft | Apr 22 | May 7 | Oct 14 | Sep 29 | 174 days |
| Morris 1 Nw | 524 ft | Apr 20 | May 6 | Oct 23 | Oct 9 | 184 days |
| Morrison | 632 ft | Apr 26 | May 11 | Oct 13 | Sep 30 | 167 days |
| Morrisonville | 630 ft | Apr 12 | Apr 27 | Oct 20 | Oct 5 | 190 days |
| Mt Carmel | 430 ft | Apr 2 | Apr 17 | Oct 31 | Oct 18 | 209 days |
| Mt Carroll | 640 ft | May 2 | May 18 | Oct 7 | Sep 24 | 154 days |
| Mt Vernon 3 Ne | 490 ft | Apr 11 | Apr 26 | Oct 22 | Oct 9 | 193 days |
| Mundelein 4 Wsw | 840 ft | Apr 29 | May 15 | Oct 20 | Oct 4 | 172 days |
| Nashville 1 E | 513 ft | Apr 7 | Apr 22 | Oct 26 | Oct 14 | 201 days |
| Neoga 4NW | 643 ft | Apr 16 | Apr 29 | Oct 20 | Oct 4 | 185 days |
| New Boston Dam 17 | 548 ft | Apr 14 | May 2 | Oct 24 | Oct 9 | 190 days |
| Newton | 531 ft | Apr 13 | Apr 29 | Oct 22 | Oct 9 | 190 days |
| Newton 6 Sse | 510 ft | Apr 13 | Apr 27 | Oct 22 | Oct 6 | 191 days |
| Normal 4NE | 790 ft | Apr 25 | May 11 | Oct 16 | Oct 2 | 172 days |
| Ogden | 675 ft | Apr 20 | May 7 | Oct 21 | Oct 8 | 182 days |
| Olney 2S | 459 ft | Apr 15 | May 3 | Oct 23 | Oct 8 | 189 days |
| Ottawa 5SW | 525 ft | Apr 20 | May 5 | Oct 22 | Oct 7 | 183 days |
| Palestine | 450 ft | Apr 12 | Apr 26 | Oct 22 | Oct 5 | 193 days |
| Pana | 650 ft | Apr 17 | May 3 | Oct 23 | Oct 8 | 188 days |
| Paris Stp | 649 ft | Apr 21 | May 9 | Oct 20 | Oct 1 | 179 days |
| Park Forest | 710 ft | Apr 23 | May 11 | Oct 20 | Oct 6 | 179 days |
| Paw Paw 2S | 889 ft | Apr 27 | May 12 | Oct 15 | Sep 30 | 171 days |
| Paxton 2 Wsw | 758 ft | Apr 23 | May 9 | Oct 12 | Sep 26 | 170 days |
| Peoria Gtr Peoria AP | 650 ft | Apr 16 | May 4 | Oct 23 | Oct 9 | 189 days |
| Perry 6 Nw | 650 ft | Apr 18 | May 5 | Oct 15 | Sep 30 | 179 days |
| Peru | 620 ft | Apr 24 | May 8 | Oct 18 | Oct 3 | 176 days |
| Petersburg 1E | 600 ft | Apr 13 | Apr 28 | Oct 21 | Oct 7 | 189 days |
| Piper City | 670 ft | Apr 25 | May 10 | Oct 20 | Oct 2 | 175 days |
| Pittsfield #2 | 670 ft | Apr 14 | Apr 30 | Oct 21 | Oct 5 | 189 days |
| Polo 5NW | 856 ft | Apr 29 | May 14 | Oct 7 | Sep 23 | 161 days |
| Pontiac | 650 ft | Apr 16 | May 2 | Oct 24 | Oct 12 | 191 days |
| Prairie City 2S | 650 ft | Apr 17 | May 2 | Oct 22 | Oct 7 | 185 days |
| Princeton | 697 ft | Apr 22 | May 7 | Oct 17 | Oct 3 | 177 days |
| Princeville | 750 ft | Apr 22 | May 6 | Oct 14 | Sep 29 | 174 days |
| Quincy Dam 21 | 483 ft | Apr 8 | Apr 23 | Oct 30 | Oct 17 | 204 days |
| Quincy Rgnl AP | 769 ft | Apr 14 | May 1 | Oct 23 | Oct 10 | 191 days |
| Ramsey | 600 ft | Apr 15 | May 1 | Oct 19 | Oct 3 | 185 days |
| Rantoul | 740 ft | Apr 21 | May 6 | Oct 18 | Oct 5 | 179 days |
| Rend Lake Dam | 455 ft | Apr 4 | Apr 19 | Oct 27 | Oct 16 | 204 days |
| Robinson | 535 ft | Apr 13 | Apr 28 | Oct 22 | Oct 7 | 190 days |
| Rochelle | 775 ft | Apr 26 | May 12 | Oct 13 | Sep 29 | 168 days |
| Rock Island L&D 15 | 568 ft | Apr 19 | May 4 | Oct 22 | Oct 7 | 184 days |
| Rockford Gtr Rockford AP | 730 ft | Apr 24 | May 8 | Oct 17 | Oct 2 | 174 days |
| Romeoville Wfo | 660 ft | Apr 20 | May 6 | Oct 22 | Oct 7 | 184 days |
| Rosiclare 5NW | 400 ft | Apr 19 | May 8 | Oct 20 | Oct 7 | 181 days |
| Rushville | 673 ft | Apr 16 | May 3 | Oct 23 | Oct 10 | 189 days |
| Salem | 550 ft | Apr 9 | Apr 23 | Oct 26 | Oct 13 | 197 days |
| Shabbona 5 Nne | 861 ft | Apr 28 | May 13 | Oct 10 | Sep 26 | 163 days |
| Shelbyville Dam | 650 ft | Apr 10 | Apr 28 | Oct 24 | Oct 8 | 195 days |
| Sidell 4N | 672 ft | Apr 19 | May 3 | Oct 19 | Oct 5 | 181 days |
| Smithland L&D | 357 ft | Apr 3 | Apr 21 | Oct 30 | Oct 17 | 207 days |
| Sparta 1 W | 535 ft | Apr 12 | Apr 29 | Oct 22 | Oct 7 | 191 days |
| Springfield #2 | 599 ft | Apr 15 | Apr 30 | Oct 22 | Oct 9 | 188 days |
| Springfield Capital AP | 594 ft | Apr 14 | Apr 29 | Oct 20 | Oct 5 | 187 days |
| Stockton 3 Nne | 970 ft | Apr 27 | May 12 | Oct 9 | Sep 26 | 165 days |
| Streamwood | 819 ft | Apr 30 | May 16 | Oct 13 | Sep 29 | 163 days |
| Streator 3 Se | 610 ft | Apr 12 | Apr 25 | Oct 28 | Oct 16 | 199 days |
| Sullivan 3S | 640 ft | Apr 15 | Apr 30 | Oct 22 | Oct 6 | 187 days |
| Tuscola | 651 ft | Apr 15 | May 1 | Oct 20 | Oct 7 | 188 days |
| Vandalia | 490 ft | Apr 10 | Apr 24 | Oct 24 | Oct 11 | 196 days |
| Virden | 675 ft | Apr 7 | Apr 21 | Oct 29 | Oct 16 | 205 days |
| Walnut | 671 ft | Apr 24 | May 9 | Oct 14 | Sep 30 | 172 days |
| Watseka 2 Nw | 620 ft | Apr 24 | May 10 | Oct 16 | Oct 1 | 174 days |
| Waukegan | 700 ft | Apr 30 | May 14 | Oct 19 | Sep 30 | 170 days |
| West Chicago Dupage AP | 754 ft | Apr 25 | May 12 | Oct 19 | Oct 5 | 174 days |
| Wheaton 3 Se | 680 ft | Apr 27 | May 14 | Oct 17 | Oct 1 | 173 days |
| White Hall 1 E | 580 ft | Apr 13 | Apr 28 | Oct 22 | Oct 9 | 190 days |
| Winchester | 551 ft | Apr 18 | May 5 | Oct 20 | Oct 5 | 183 days |
| Windsor | 690 ft | Apr 16 | Apr 30 | Oct 22 | Oct 8 | 187 days |
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