Illinois frost dates: Last spring and first autumn frost at every NOAA station, 1991-2020
Across Illinois's 170 NOAA stations with frost dates, the median last spring frost (32°F) runs from April 2 in Cairo to May 2 in Mount Carroll; for half of its places it comes after April 19.
- Typical last spring frost
- April 19median of 144 places
- Typical first autumn frost
- October 20median of 144 places
- Earliest last frost
- April 2Cairo
- Latest last frost
- May 2Mount Carroll
When is the last frost in Illinois, town by town?
Each date is NOAA's: "after April 19 in half of years" means the last 32°F night of spring came after April 19 in half of the years 1991-2020. By the 1-in-10 date, the last frost has passed in nine years out of ten.
Find your town in the list, or look up a ZIP code for the stations nearest it.
| Place or station | Last frost (median) | 1 in 10 after | First frost (median) | 1 in 10 before | Growing season | Zone |
|---|---|---|---|---|---|---|
| Cairo3 mi N | April 2 | April 17 | October 31 | October 18 | 211 days | – |
| Mount Carmel | April 2 | April 17 | October 31 | October 18 | 209 days | – |
| Brownstown4 mi SW | April 3 | April 25 | October 24 | October 9 | 202 days | – |
| Grand Chain Dam 53 | April 3 | April 21 | November 5 | October 23 | 216 days | – |
| Smithland Lock and Dam | April 3 | April 21 | October 30 | October 17 | 207 days | 7a |
| Albion | April 4 | April 20 | October 28 | October 15 | 206 days | – |
| AltonAlton - Melvin Price Lock and Dam | April 4 | April 19 | November 5 | October 25 | 214 days | – |
| Benton2 mi N | April 4 | April 21 | October 28 | October 15 | 206 days | – |
| Rend Lake Dam | April 4 | April 19 | October 27 | October 16 | 204 days | – |
| BrookportBrookport Dam 52 | April 6 | April 23 | October 27 | October 15 | 203 days | 7a |
| Cahokia | April 6 | April 20 | October 27 | October 14 | 203 days | 6b |
| CarlyleCarlyle Reservoir | April 6 | April 22 | October 29 | October 16 | 204 days | 6b |
| Du Quoin4 mi SE | April 6 | April 22 | October 22 | October 9 | 199 days | 6b |
| FairfieldFairfield Radio WFIW | April 7 | April 23 | October 26 | October 14 | 201 days | 6b |
| Grayville | April 7 | April 23 | October 25 | October 12 | 201 days | – |
| Harrisburg | April 7 | April 25 | October 26 | October 10 | 202 days | – |
| Nashville1 mi E | April 7 | April 22 | October 26 | October 14 | 201 days | 6b |
| Virden | April 7 | April 21 | October 29 | October 16 | 205 days | 6a |
| Anna2 mi NNE | April 8 | April 26 | October 29 | October 17 | 203 days | – |
| Cahokia HeightsCahokia St Louis Airport | April 8 | April 23 | October 26 | October 12 | 200 days | 7a |
| GladstoneGladstone Dam 18 | April 8 | April 23 | October 29 | October 17 | 202 days | 6a |
| KaskaskiaKaskaskia River Navigation Lock | April 8 | April 25 | October 30 | October 15 | 202 days | 7a |
| LawrencevilleLawrenceville International Airport | April 8 | April 22 | October 26 | October 13 | 200 days | 6b |
| Quincy Dam 21 | April 8 | April 23 | October 30 | October 17 | 204 days | 6a |
| CarbondaleCarbondale Southern Illinois Airport | April 9 | April 25 | October 22 | October 8 | 195 days | 7a |
| Carbondale Sewage Plant | April 9 | April 25 | October 22 | October 10 | 195 days | 6b |
| Flora | April 9 | April 23 | October 24 | October 11 | 198 days | 6b |
| Iuka (12 mi SW) | April 9 | April 25 | October 24 | October 10 | 196 days | 6b |
| Salem | April 9 | April 23 | October 26 | October 13 | 197 days | 6b |
| BurbankChicago Midway Airport (3 mi SW) | April 10 | April 26 | November 1 | October 21 | 203 days | – |
| Chicago Northerly Island | April 10 | April 25 | November 5 | October 24 | 208 days | – |
| Flora (5 mi NW) | April 10 | April 26 | October 23 | October 7 | 196 days | – |
| ShelbyvilleShelbyville Dam | April 10 | April 28 | October 24 | October 8 | 195 days | 6b |
| Vandalia | April 10 | April 24 | October 24 | October 11 | 196 days | 6b |
| Chicago Midway Airport | April 11 | April 27 | October 31 | October 20 | 201 days | 6a |
| Mattoon station | April 11 | April 28 | October 29 | October 15 | 199 days | – |
| McLeansboro | April 11 | April 26 | October 21 | October 6 | 190 days | – |
| Mount Vernon3 mi NE | April 11 | April 26 | October 22 | October 9 | 193 days | 6b |
| BellevilleBelleville Siu Research | April 12 | April 28 | October 20 | October 3 | 189 days | 6b |
| Lawrenceville (2 mi WSW) | April 12 | April 30 | October 25 | October 12 | 193 days | – |
| Morrisonville | April 12 | April 27 | October 20 | October 5 | 190 days | 6a |
| Palestine | April 12 | April 26 | October 22 | October 5 | 193 days | 6a |
| Sparta1 mi W | April 12 | April 29 | October 22 | October 7 | 191 days | 6b |
| Streator3 mi SE | April 12 | April 25 | October 28 | October 16 | 199 days | – |
| Bentley | April 13 | April 30 | October 22 | October 8 | 191 days | 6a |
| Effingham3 mi SW | April 13 | April 29 | October 24 | October 9 | 191 days | 6b |
| FultonFulton Lock and Dam #13 | April 13 | April 28 | October 26 | October 13 | 195 days | 5b |
| Hillsboro | April 13 | April 28 | October 24 | October 10 | 192 days | 6b |
| Newton | April 13 | April 29 | October 22 | October 9 | 190 days | 6b |
| Newton (6 mi SSE) | April 13 | April 27 | October 22 | October 6 | 191 days | – |
| Petersburg1 mi E | April 13 | April 28 | October 21 | October 7 | 189 days | – |
| Robinson | April 13 | April 28 | October 22 | October 7 | 190 days | – |
| White Hall1 mi E | April 13 | April 28 | October 22 | October 9 | 190 days | 6a |
| Carlinville | April 14 | April 30 | October 21 | October 5 | 188 days | 6b |
| Casey | April 14 | April 30 | October 20 | October 5 | 187 days | – |
| Decatur Water Treatment Plant | April 14 | May 1 | October 24 | October 11 | 192 days | 6a |
| Dixon Springs Agricultural Center | April 14 | April 30 | October 21 | October 6 | 189 days | 7a |
| Jerseyville2 mi SW | April 14 | April 30 | October 19 | October 7 | 187 days | 6a |
| New BostonNew Boston Dam 17 | April 14 | May 2 | October 24 | October 9 | 190 days | 5b |
| PittsfieldPittsfield #2 | April 14 | April 30 | October 21 | October 5 | 189 days | – |
| QuincyQuincy Regional Airport | April 14 | May 1 | October 23 | October 10 | 191 days | 6a |
| SpringfieldSpringfield Abraham Lincoln Capital Airport | April 14 | April 29 | October 20 | October 5 | 187 days | 6a |
| CarmiCarmi 3 | April 15 | May 2 | October 19 | October 4 | 183 days | 6b |
| Champaign (3 mi S) | April 15 | April 29 | October 24 | October 11 | 190 days | – |
| Charleston | April 15 | May 3 | October 23 | October 9 | 187 days | 6a |
| MattoonMattoon Coles County Airport | April 15 | April 30 | October 24 | October 9 | 189 days | 6b |
| Olney2 mi S | April 15 | May 3 | October 23 | October 8 | 189 days | 6b |
| Ramsey | April 15 | May 1 | October 19 | October 3 | 185 days | 6a |
| Springfield #2 | April 15 | April 30 | October 22 | October 9 | 188 days | – |
| Sullivan3 mi S | April 15 | April 30 | October 22 | October 6 | 187 days | – |
| Tuscola | April 15 | May 1 | October 20 | October 7 | 188 days | 6a |
| ChannahonChannahon Dresden Island Dam | April 16 | May 3 | October 26 | October 13 | 191 days | – |
| ChicagoChicago O'Hare International Airport | April 16 | May 1 | October 28 | October 15 | 193 days | 6a |
| DecaturDecatur Airport | April 16 | April 30 | October 22 | October 7 | 187 days | 6b |
| Neoga4 mi NW | April 16 | April 29 | October 20 | October 4 | 185 days | – |
| PeoriaGeneral Wayne A. Downing International Airport | April 16 | May 4 | October 23 | October 9 | 189 days | 6a |
| Pontiac | April 16 | May 2 | October 24 | October 12 | 191 days | 6a |
| Rushville | April 16 | May 3 | October 23 | October 10 | 189 days | 6a |
| Windsor | April 16 | April 30 | October 22 | October 8 | 187 days | 6b |
| Havana | April 17 | May 3 | October 19 | October 1 | 185 days | 6a |
| JacksonvilleJacksonville 2 | April 17 | May 1 | October 21 | October 9 | 186 days | – |
| Mason City4 mi SE | April 17 | May 4 | October 18 | October 4 | 182 days | – |
| Pana | April 17 | May 3 | October 23 | October 8 | 188 days | 6b |
| Prairie City2 mi S | April 17 | May 2 | October 22 | October 7 | 185 days | 5b |
| Golden | April 18 | May 1 | October 21 | October 6 | 187 days | – |
| Hennepin | April 18 | May 3 | October 22 | October 7 | 188 days | – |
| Illinois CityIllinois City Dam 16 | April 18 | May 2 | October 24 | October 11 | 188 days | – |
| Perry6 mi NW | April 18 | May 5 | October 15 | September 30 | 179 days | 6a |
| Winchester | April 18 | May 5 | October 20 | October 5 | 183 days | – |
| Athens4 mi SW | April 19 | May 4 | October 19 | October 5 | 181 days | – |
| Aurora | April 19 | May 4 | October 23 | October 9 | 185 days | 5b |
| ChampaignChampaign Willard Airport | April 19 | May 5 | October 17 | October 3 | 180 days | 6a |
| Jacksonville (2 mi E) | April 19 | May 5 | October 17 | October 1 | 179 days | 6a |
| JolietJoliet Brandon Rd Dam | April 19 | May 7 | October 25 | October 12 | 188 days | 6a |
| KankakeeKankakee Metro Wastewater | April 19 | May 3 | October 24 | October 12 | 188 days | 6a |
| Little Red School House | April 19 | May 5 | October 22 | October 8 | 183 days | – |
| Rock IslandRock Island Lock and Dam 15 | April 19 | May 4 | October 22 | October 7 | 184 days | 6a |
| Rosiclare5 mi NW | April 19 | May 8 | October 20 | October 7 | 181 days | 6b |
| Sidell4 mi N | April 19 | May 3 | October 19 | October 5 | 181 days | 6a |
| WheelingChicago Palwaukee Airport | April 19 | May 3 | October 26 | October 13 | 190 days | 6a |
| Galesburg | April 20 | May 5 | October 19 | October 4 | 180 days | 5b |
| Geneseo | April 20 | May 6 | October 20 | October 5 | 180 days | 5b |
| Lacon | April 20 | May 7 | October 17 | October 3 | 178 days | 6a |
| Lincoln | April 20 | May 4 | October 16 | October 3 | 179 days | 6a |
| Morris1 mi NW | April 20 | May 6 | October 23 | October 9 | 184 days | 5b |
| Ogden | April 20 | May 7 | October 21 | October 8 | 182 days | 6a |
| Ottawa5 mi SW | April 20 | May 5 | October 22 | October 7 | 183 days | 6a |
| RomeovilleRomeoville Weather Office | April 20 | May 6 | October 22 | October 7 | 184 days | 5b |
| Bloomington5 mi W | April 21 | May 5 | October 20 | October 9 | 181 days | 6a |
| Congerville2 mi NW | April 21 | May 7 | October 17 | October 3 | 178 days | 5b |
| Danville | April 21 | May 7 | October 20 | October 6 | 181 days | 6a |
| Dixon1 mi W | April 21 | May 5 | October 19 | October 4 | 180 days | 5a |
| Gibson City | April 21 | May 5 | October 17 | October 5 | 178 days | 6a |
| Knoxville | April 21 | May 6 | October 20 | October 7 | 181 days | 5b |
| La Harpe | April 21 | May 5 | October 19 | October 4 | 180 days | 5b |
| ParisParis Stp | April 21 | May 9 | October 20 | October 1 | 179 days | 6a |
| Rantoul | April 21 | May 6 | October 18 | October 5 | 179 days | 6a |
| Aledo | April 22 | May 6 | October 19 | October 6 | 181 days | 5b |
| Avon | April 22 | May 8 | October 19 | October 5 | 177 days | – |
| Hoopeston | April 22 | May 8 | October 19 | October 5 | 180 days | 6a |
| Monmouth | April 22 | May 10 | October 15 | September 29 | 174 days | 5b |
| Monmouth (4 mi NW) | April 22 | May 7 | October 14 | September 29 | 174 days | – |
| Princeton | April 22 | May 7 | October 17 | October 3 | 177 days | 5b |
| Princeville | April 22 | May 6 | October 14 | September 29 | 174 days | 5b |
| Antioch | April 23 | May 9 | October 21 | October 6 | 179 days | – |
| Champaign (9 mi SW) | April 23 | May 9 | October 13 | September 28 | 170 days | 5b |
| Chenoa | April 23 | May 7 | October 15 | September 29 | 174 days | 5b |
| Park Forest | April 23 | May 11 | October 20 | October 6 | 179 days | 6a |
| Paxton2 mi WSW | April 23 | May 9 | October 12 | September 26 | 170 days | 6a |
| DeKalbDe Kalb | April 24 | May 10 | October 18 | October 4 | 177 days | 5b |
| Hennepin Water Treatment Plant | April 24 | May 10 | October 17 | October 1 | 174 days | – |
| Kewanee1 mi E | April 24 | May 8 | October 17 | October 3 | 175 days | 5b |
| Lake Villa2 mi NE | April 24 | May 9 | October 23 | October 8 | 180 days | 5b |
| MolineMoline Quad City International Airport | April 24 | May 9 | October 18 | October 4 | 176 days | 5b |
| Peru | April 24 | May 8 | October 18 | October 3 | 176 days | 5b |
| RockfordRockford Greater Rockford Airport | April 24 | May 8 | October 17 | October 2 | 174 days | 5b |
| Walnut | April 24 | May 9 | October 14 | September 30 | 172 days | 5b |
| Watseka2 mi NW | April 24 | May 10 | October 16 | October 1 | 174 days | 5b |
| Barrington3 mi SW | April 25 | May 12 | October 19 | October 5 | 177 days | 5b |
| Crystal Lake4 mi NW | April 25 | May 9 | October 22 | October 7 | 179 days | – |
| Normal4 mi NE | April 25 | May 11 | October 16 | October 2 | 172 days | 6a |
| Piper City | April 25 | May 10 | October 20 | October 2 | 175 days | 6a |
| West ChicagoWest Chicago Dupage Airport | April 25 | May 12 | October 19 | October 5 | 174 days | 5b |
| Chicago Botanic Garden | April 26 | May 11 | October 21 | October 5 | 176 days | 6a |
| Elgin | April 26 | May 12 | October 18 | October 3 | 174 days | 5b |
| FreeportFreeport Waste Water Treatment Plant | April 26 | May 11 | October 13 | September 30 | 169 days | 5b |
| Galena | April 26 | May 11 | October 15 | October 1 | 170 days | – |
| Galva | April 26 | May 11 | October 12 | September 25 | 166 days | 5b |
| Minonk | April 26 | May 10 | October 17 | October 1 | 173 days | 5b |
| Morrison | April 26 | May 11 | October 13 | September 30 | 167 days | 5a |
| Rochelle | April 26 | May 12 | October 13 | September 29 | 168 days | 5b |
| Compton1 mi NW | April 27 | May 14 | October 12 | September 27 | 167 days | – |
| Dwight | April 27 | May 14 | October 15 | September 30 | 170 days | 5b |
| MarseillesMarseilles Lock | April 27 | May 13 | October 17 | October 3 | 171 days | 5b |
| Paw Paw2 mi S | April 27 | May 12 | October 15 | September 30 | 171 days | 5b |
| Stockton3 mi NNE | April 27 | May 12 | October 9 | September 26 | 165 days | 5a |
| Wheaton3 mi SE | April 27 | May 14 | October 17 | October 1 | 173 days | 5b |
| Altona | April 28 | May 12 | October 12 | September 28 | 165 days | – |
| Chicago Aurora Municipal Airport | April 28 | May 11 | October 13 | September 27 | 166 days | 5a |
| LisleLisle-Morton Arboretum | April 28 | May 14 | October 16 | October 1 | 169 days | 5b |
| Marengo | April 28 | May 14 | October 12 | September 28 | 166 days | – |
| Shabbona5 mi NNE | April 28 | May 13 | October 10 | September 26 | 163 days | 5b |
| Mundelein4 mi WSW | April 29 | May 15 | October 20 | October 4 | 172 days | 5b |
| Polo5 mi NW | April 29 | May 14 | October 7 | September 23 | 161 days | 5a |
| Chicago Waukegan Regional Airport | April 30 | May 16 | October 21 | October 5 | 173 days | 6a |
| Streamwood | April 30 | May 16 | October 13 | September 29 | 163 days | 5b |
| Waukegan | April 30 | May 14 | October 19 | September 30 | 170 days | – |
| Elizabeth | May 1 | May 17 | October 9 | September 25 | 160 days | 5a |
| McHenry W.G. Stratton Lock and Dam | May 1 | May 19 | October 11 | September 27 | 162 days | 5b |
| Mount Carroll | May 2 | May 18 | October 7 | September 24 | 154 days | 5a |
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities, growing-season length); station daily lows via ACIS (zone). Growing season: NOAA's median number of days between the last spring and first autumn 32°F night. Zone: the USDA's plant hardiness rule applied to the station's own 1991-2020 coldest nights.