Frost Dates and Planting Windows in Illinois

The 32°F frost dates at the 170 weather stations in Illinois with NOAA's 1991–2020 Climate Normals, and the planting windows they give. These are long-term statistics, not a forecast. For the dates at the station nearest you, enter your ZIP code.

Frost dates across Illinois

Each risk level uses a date with a set chance of frost. In spring, it's the chance of a 32°F frost on or after the last-frost date. In fall, it's the chance of the first 32°F frost on or before the first-frost date. At the Typical level (30%), the last frost ranges from April 7 to May 9 across the state, and the first frost from October 1 to November 1.

32°F frost dates: earliest and latest among 170 stations, by risk level
Risk level	Earliest last frost	Latest last frost	Earliest first frost	Latest first frost
Conservative (10%)	April 172 stations	May 19MC HENRY -WG STRATTON L&D, IL US	September 23POLO 5NW, IL US	October 25ALTON - MELVIN PRICE L&D, IL US
Typical (30%)	April 7MT CARMEL, IL US	May 9MT CARROLL, IL US	October 1POLO 5NW, IL US	November 1CHICAGO NORTHERLY IS, IL US
Aggressive (50%)	April 22 stations	May 2MT CARROLL, IL US	October 72 stations	November 53 stations

Growing season length

The growing season is the stretch between the last spring frost and the first fall frost at 32°F. NOAA gives it as a length with a chance of being at least that long. Each risk level uses the length with that chance of a shorter season, so Conservative shows the shortest lengths.

Growing season at 32°F: shortest and longest among 170 stations
Risk level	Shortest	Longest
Conservative (90% chance of at least this long)	136 daysMT CARROLL, IL US	194 days2 stations
Typical (70% chance of at least this long)	147 daysMT CARROLL, IL US	206 days2 stations
Aggressive (50% chance of at least this long)	154 daysMT CARROLL, IL US	216 daysGRAND CHAIN DAM 53, IL US

Number of stations by growing season length, Typical (70% chance of at least this long)
Growing season	Stations
140–159 days	13
160–179 days	87
180–199 days	66
200–219 days	4

Planting windows across Illinois

For each crop, the earliest start and the latest end of its Typical windows among the stations. A window at any one station is shorter and falls inside this span. Transplant dates are for seedlings.

Typical planting windows (30% frost dates): earliest start and latest end among stations
Crop and task	Earliest start	Latest end	Stations
Basil: Transplant outdoors	April 21	May 23	170 of 170
Bean: Sow outdoors	April 7	May 9	170 of 170
Beet: Sow outdoors	March 10	May 9	170 of 170
Beet: Sow for fall	July 9	September 12	170 of 170
Broccoli: Transplant outdoors	March 10	April 25	170 of 170
Broccoli: Transplant for fall	June 29	September 12	170 of 170
Brussels sprouts: Transplant outdoors	March 10	April 25	170 of 170
Brussels sprouts: Transplant for fall	June 9	September 22	170 of 170
Cabbage: Transplant outdoors	March 10	April 25	170 of 170
Cabbage: Transplant for fall	June 24	September 12	170 of 170
Cantaloupe: Transplant outdoors	April 21	May 23	170 of 170
Cantaloupe: Sow outdoors	April 21	May 23	170 of 170
Carrot: Sow outdoors	March 10	May 9	170 of 170
Carrot: Sow for fall	June 29	September 2	170 of 170
Cucumber: Transplant outdoors	April 14	May 16	170 of 170
Cucumber: Sow outdoors	April 7	May 9	170 of 170
Eggplant: Transplant outdoors	April 21	May 23	170 of 170
Garlic: Plant for fall	October 1	November 15	170 of 170
Lettuce: Transplant outdoors	March 10	April 25	170 of 170
Lettuce: Sow outdoors	March 10	April 25	170 of 170
Lettuce: Sow for fall	June 29	September 22	170 of 170
Onion: Transplant or plant sets	March 10	April 25	170 of 170
Peas: Sow outdoors	March 10	April 25	170 of 170
Peas: Sow for fall	July 7	September 12	170 of 170
Pepper: Transplant outdoors	April 21	May 23	170 of 170
Potato: Plant seed potatoes	March 10	May 9	170 of 170
Pumpkin: Sow outdoors	April 21	May 23	170 of 170
Radish: Sow outdoors	March 10	April 25	170 of 170
Radish: Sow for fall	August 13	October 12	170 of 170
Spinach: Transplant outdoors	March 10	April 25	170 of 170
Spinach: Sow outdoors	March 10	April 25	170 of 170
Spinach: Sow for fall	July 19	September 25	170 of 170
Summer squash: Transplant outdoors	April 14	May 16	170 of 170
Summer squash: Sow outdoors	April 7	May 9	170 of 170
Sweet corn: Sow outdoors	April 7	May 9	170 of 170
Sweet potato: Plant slips	April 14	May 23	170 of 170
Tomato: Transplant outdoors	April 21	May 23	170 of 170
Turnip: Sow outdoors	March 10	April 25	170 of 170
Turnip: Sow for fall	July 19	September 22	170 of 170
Watermelon: Transplant outdoors	April 21	May 23	170 of 170
Watermelon: Sow outdoors	April 21	May 23	170 of 170

Weather stations in Illinois

Every station in Illinois with NOAA frost-date normals, with its Typical 32°F frost dates and growing season.

Typical (30%) 32°F frost dates by station
Station	Elevation	Last frost	First frost	Growing season
ALBION, IL US	530 ft	April 10	October 23	198 days
ALEDO, IL US	730 ft	April 29	October 14	172 days
ALTON - MELVIN PRICE L&D, IL US	400 ft	April 9	October 31	206 days
ALTONA, IL US	770 ft	May 3	October 6	157 days
ANNA 2 NNE, IL US	640 ft	April 16	October 24	194 days
ANTIOCH, IL US	750 ft	April 30	October 16	170 days
ATHENS 4SW, IL US	590 ft	April 25	October 13	172 days
AURORA, IL US	660 ft	April 25	October 18	177 days
AVON, IL US	640 ft	April 29	October 13	169 days
BARRINGTON 3SW, IL US	880 ft	May 1	October 14	167 days
BELLEVILLE SIU RSCH, IL US	450 ft	April 19	October 14	180 days
BENTLEY, IL US	650 ft	April 20	October 17	183 days
BENTON 2 N, IL US	440 ft	April 11	October 22	198 days
BLOOMINGTON 5W, IL US	850 ft	April 26	October 15	174 days
BROOKPORT DAM 52, IL US	330 ft	April 12	October 23	195 days
BROWNSTOWN 4 SW, IL US	530 ft	April 12	October 19	191 days
CAHOKIA ST LOUIS AP, IL US	410 ft	April 14	October 21	192 days
CAHOKIA, IL US	400 ft	April 12	October 22	195 days
CAIRO 3N, IL US	310 ft	April 8	October 26	203 days
CARBONDALE SEWAGE PLT, IL US	390 ft	April 16	October 18	186 days
CARBONDALE SOUTHERN IL AP, IL US	410 ft	April 16	October 17	187 days
CARLINVILLE, IL US	620 ft	April 20	October 15	179 days
CARLYLE RSVR, IL US	500 ft	April 13	October 24	196 days
CARMI 3, IL US	330 ft	April 23	October 12	174 days
CASEY, IL US	620 ft	April 20	October 14	179 days
CHAMPAIGN 3S, IL US	720 ft	April 21	October 19	182 days
CHAMPAIGN 9 SW, IL US	700 ft	April 30	October 6	161 days
CHAMPAIGN WILLARD AP, IL US	750 ft	April 26	October 12	171 days
CHANNAHON DRESDEN ISL DAM, IL US	500 ft	April 22	October 21	184 days
CHARLESTON, IL US	700 ft	April 22	October 17	177 days
CHENOA, IL US	720 ft	April 29	October 9	165 days
CHICAGO AURORA MUNI AP, IL US	710 ft	May 4	October 6	158 days
CHICAGO BOTANIC GARDEN, IL US	630 ft	May 2	October 14	167 days
CHICAGO MIDWAY AP 3SW, IL US	620 ft	April 17	October 28	195 days
CHICAGO MIDWAY AP, IL US	610 ft	April 17	October 26	193 days
CHICAGO NORTHERLY IS, IL US	580 ft	April 17	November 1	199 days
CHICAGO OHARE INTL AP, IL US	660 ft	April 22	October 24	185 days
CHICAGO PALWAUKEE AP, IL US	640 ft	April 25	October 22	183 days
CHICAGO WAUKEGAN RGNL AP, IL US	730 ft	May 6	October 15	165 days
COMPTON 1 NW, IL US	900 ft	May 3	October 5	157 days
CONGERVILLE 2NW, IL US	640 ft	April 28	October 10	169 days
CRYSTAL LAKE 4NW, IL US	940 ft	May 1	October 17	170 days
DANVILLE, IL US	560 ft	April 27	October 15	172 days
DE KALB, IL US	870 ft	April 30	October 13	167 days
DECATUR AP, IL US	670 ft	April 22	October 16	178 days
DECATUR WTP, IL US	640 ft	April 20	October 18	183 days
DIXON 1W, IL US	660 ft	April 28	October 14	172 days
DIXON SPRINGS AGRIC CTR, IL US	530 ft	April 20	October 16	180 days
DU QUOIN 4 SE, IL US	420 ft	April 13	October 17	189 days
DWIGHT, IL US	630 ft	May 3	October 9	160 days
EFFINGHAM 3SW, IL US	630 ft	April 19	October 18	183 days
ELGIN, IL US	760 ft	May 1	October 12	165 days
ELIZABETH, IL US	670 ft	May 7	October 3	152 days
FAIRFIELD RADIO WFIW, IL US	430 ft	April 13	October 22	192 days
FLORA 5 NW, IL US	500 ft	April 17	October 17	187 days
FLORA, IL US	480 ft	April 15	October 20	190 days
FREEPORT WASTE WTP, IL US	750 ft	May 2	October 8	162 days
FULTON L&D #13, IL US	590 ft	April 18	October 21	186 days
GALENA, IL US	820 ft	May 2	October 10	162 days
GALESBURG, IL US	760 ft	April 26	October 13	172 days
GALVA, IL US	810 ft	May 2	October 6	158 days
GENESEO, IL US	640 ft	April 26	October 15	173 days
GIBSON CITY, IL US	750 ft	April 27	October 12	170 days
GLADSTONE DAM 18, IL US	540 ft	April 14	October 25	195 days
GOLDEN, IL US	720 ft	April 23	October 15	178 days
GRAND CHAIN DAM 53, IL US	380 ft	April 9	October 31	206 days
GRAYVILLE, IL US	440 ft	April 14	October 21	193 days
HARRISBURG, IL US	370 ft	April 14	October 21	194 days
HAVANA, IL US	460 ft	April 22	October 13	175 days
HENNEPIN WTR TRMT PLT, IL US	460 ft	May 1	October 11	167 days
HENNEPIN, IL US	520 ft	April 23	October 17	179 days
HILLSBORO, IL US	630 ft	April 19	October 18	184 days
HOOPESTON, IL US	710 ft	April 29	October 14	171 days
ILLINOIS CITY DAM 16, IL US	550 ft	April 24	October 19	181 days
IUKA 12 SW, IL US	590 ft	April 15	October 18	187 days
JACKSONVILLE 2, IL US	630 ft	April 23	October 17	178 days
JACKSONVILLE 2E, IL US	610 ft	April 26	October 11	170 days
JERSEYVILLE 2 SW, IL US	630 ft	April 21	October 15	179 days
JOLIET BRANDON RD DAM, IL US	540 ft	April 26	October 20	179 days
KANKAKEE METRO WASTEWATER, IL US	600 ft	April 25	October 20	179 days
KASKASKIA RVR NAVIGATION LOCK, IL US	380 ft	April 15	October 24	193 days
KEWANEE 1 E, IL US	780 ft	April 30	October 12	167 days
KNOXVILLE, IL US	730 ft	April 27	October 15	173 days
LA HARPE, IL US	690 ft	April 27	October 14	172 days
LACON, IL US	460 ft	April 28	October 12	169 days
LAKE VILLA 2NE, IL US	840 ft	April 30	October 17	171 days
LAWRENCEVILLE 2WSW, IL US	450 ft	April 19	October 20	185 days
LAWRENCEVILLE INTL AP, IL US	430 ft	April 14	October 22	193 days
LINCOLN, IL US	580 ft	April 25	October 11	170 days
LISLE-MORTON ARBORETUM, IL US	680 ft	May 4	October 11	160 days
LITTLE RED SCHOOL HSE, IL US	710 ft	April 25	October 17	175 days
MARENGO, IL US	810 ft	May 4	October 6	157 days
MARSEILLES LOCK, IL US	490 ft	May 3	October 12	163 days
MASON CITY 4SE, IL US	600 ft	April 23	October 13	173 days
MATTOON COLES CO AP, IL US	720 ft	April 20	October 18	182 days
MATTOON, IL US	700 ft	April 18	October 24	190 days
MC HENRY -WG STRATTON L&D, IL US	740 ft	May 8	October 5	154 days
MCLEANSBORO, IL US	450 ft	April 18	October 15	182 days
MINONK, IL US	750 ft	May 1	October 12	164 days
MOLINE QUAD CITY INTL AP, IL US	590 ft	April 30	October 13	168 days
MONMOUTH 4NW, IL US	720 ft	April 29	October 9	166 days
MONMOUTH, IL US	720 ft	April 30	October 9	166 days
MORRIS 1 NW, IL US	520 ft	April 27	October 18	176 days
MORRISON, IL US	630 ft	May 2	October 9	160 days
MORRISONVILLE, IL US	630 ft	April 17	October 15	181 days
MT CARMEL, IL US	430 ft	April 7	October 26	201 days
MT CARROLL, IL US	640 ft	May 9	October 2	147 days
MT VERNON 3 NE, IL US	490 ft	April 17	October 18	186 days
MUNDELEIN 4 WSW, IL US	840 ft	May 5	October 14	163 days
NASHVILLE 1 E, IL US	510 ft	April 13	October 22	194 days
NEOGA 4NW, IL US	640 ft	April 21	October 13	176 days
NEW BOSTON DAM 17, IL US	550 ft	April 21	October 19	181 days
NEWTON 6 SSE, IL US	510 ft	April 19	October 16	183 days
NEWTON, IL US	530 ft	April 18	October 17	182 days
NORMAL 4NE, IL US	790 ft	May 1	October 11	164 days
OGDEN, IL US	670 ft	April 26	October 16	174 days
OLNEY 2S, IL US	460 ft	April 22	October 17	181 days
OTTAWA 5SW, IL US	520 ft	April 26	October 17	175 days
PALESTINE, IL US	450 ft	April 18	October 16	185 days
PANA, IL US	650 ft	April 24	October 17	179 days
PARIS STP, IL US	650 ft	April 27	October 14	170 days
PARK FOREST, IL US	710 ft	April 30	October 15	172 days
PAW PAW 2S, IL US	890 ft	May 3	October 9	163 days
PAXTON 2 WSW, IL US	760 ft	April 30	October 5	162 days
PEORIA GTR PEORIA AP, IL US	650 ft	April 23	October 18	180 days
PERRY 6 NW, IL US	650 ft	April 25	October 10	170 days
PERU, IL US	620 ft	April 30	October 12	167 days
PETERSBURG 1E, IL US	600 ft	April 18	October 16	181 days
PIPER CITY, IL US	670 ft	May 1	October 13	167 days
PITTSFIELD #2, IL US	670 ft	April 21	October 15	180 days
POLO 5NW, IL US	860 ft	May 5	October 1	152 days
PONTIAC, IL US	650 ft	April 22	October 20	182 days
PRAIRIE CITY 2S, IL US	650 ft	April 23	October 17	177 days
PRINCETON, IL US	700 ft	April 29	October 12	168 days
PRINCEVILLE, IL US	750 ft	April 29	October 8	166 days
QUINCY DAM 21, IL US	480 ft	April 15	October 25	194 days
QUINCY RGNL AP, IL US	770 ft	April 21	October 17	182 days
RAMSEY, IL US	600 ft	April 21	October 14	176 days
RANTOUL, IL US	740 ft	April 27	October 12	171 days
REND LAKE DAM, IL US	460 ft	April 10	October 23	197 days
ROBINSON, IL US	540 ft	April 18	October 16	181 days
ROCHELLE, IL US	770 ft	May 2	October 8	159 days
ROCK ISLAND L&D 15, IL US	570 ft	April 24	October 17	177 days
ROCKFORD GTR ROCKFORD AP, IL US	730 ft	April 30	October 12	166 days
ROMEOVILLE WFO, IL US	660 ft	April 27	October 17	175 days
ROSICLARE 5NW, IL US	400 ft	April 27	October 15	173 days
RUSHVILLE, IL US	670 ft	April 23	October 18	181 days
SALEM, IL US	550 ft	April 14	October 21	190 days
SHABBONA 5 NNE, IL US	860 ft	May 4	October 4	154 days
SHELBYVILLE DAM, IL US	650 ft	April 17	October 18	186 days
SIDELL 4N, IL US	670 ft	April 24	October 13	174 days
SMITHLAND L&D, IL US	360 ft	April 10	October 25	199 days
SPARTA 1 W, IL US	540 ft	April 19	October 17	182 days
SPRINGFIELD #2, IL US	600 ft	April 20	October 17	180 days
SPRINGFIELD CAPITAL AP, IL US	590 ft	April 20	October 15	178 days
STOCKTON 3 NNE, IL US	970 ft	May 3	October 3	157 days
STREAMWOOD, IL US	820 ft	May 6	October 8	156 days
STREATOR 3 SE, IL US	610 ft	April 18	October 23	191 days
SULLIVAN 3S, IL US	640 ft	April 20	October 17	179 days
TUSCOLA, IL US	650 ft	April 21	October 15	180 days
VANDALIA, IL US	490 ft	April 17	October 19	188 days
VIRDEN, IL US	670 ft	April 13	October 25	197 days
WALNUT, IL US	670 ft	April 30	October 8	164 days
WATSEKA 2 NW, IL US	620 ft	April 30	October 10	166 days
WAUKEGAN, IL US	700 ft	May 4	October 12	162 days
WEST CHICAGO DUPAGE AP, IL US	750 ft	May 1	October 14	166 days
WHEATON 3 SE, IL US	680 ft	May 3	October 10	163 days
WHITE HALL 1 E, IL US	580 ft	April 20	October 17	182 days
WINCHESTER, IL US	550 ft	April 24	October 14	174 days
WINDSOR, IL US	690 ft	April 22	October 17	177 days

Data sources

NOAA U.S. Climate Normals, frost dates, 1991–2020 normals, version 1.0.1: Files: us-climate-normals_1991-2020_v1.0.1_annualseasonal_multivariate_by-station_c20230404.tar.gz, inventory_30yr.txt from NOAA NCEI. Retrieved October 10, 2026.