Illinois Frost Dates: Last and First Frost by Town

170 NOAA weather stations · 1991–2020 U.S. Climate Normals · Data updated 2026-10-29

Quick answer

Across Illinois's 170 NOAA stations with regular frost, the median last spring frost is April 18 and the median first fall frost is October 21. Last frost dates range from April 2 at Cairo 3N to May 2 at Mount Carroll, so enter your ZIP code below for the station nearest you.

How frost dates vary across Illinois

North vs south: stations in the northern third of the state (north of 41.2°N) reach their median last frost about 14 days later than the southern third (south of 39.5°N).
Safety margin: the median 10%-risk date (May 3) is about 15 days after the median last frost. Waiting until then cuts the chance of a killing frost on tender transplants from 1 in 2 to 1 in 10.

Frost dates at Illinois's major weather stations

These National Weather Service stations, mostly at airports, have the longest and most complete records in the state.


Belleville Siu Rsch	450	Apr 12	Apr 28	Oct 20	189
Cahokia St Louis Airport	413	Apr 8	Apr 23	Oct 26	200
Cairo 3N	313	Apr 2	Apr 17	Oct 31	211
Carbondale Southern Il Airport	406	Apr 9	Apr 25	Oct 22	195
Champaign 9 SW	700	Apr 23	May 9	Oct 13	170
Champaign Willard Airport	754	Apr 19	May 5	Oct 17	180
Chicago Aurora Municipal Airport	710	Apr 28	May 11	Oct 13	166
Chicago Midway Airport	612	Apr 11	Apr 27	Oct 31	201
Chicago Ohare Intl Airport	658	Apr 16	May 1	Oct 28	193
Chicago Palwaukee Airport	636	Apr 19	May 3	Oct 26	190
Chicago Waukegan Regional Airport	727	Apr 30	May 16	Oct 21	173
Decatur Airport	675	Apr 16	Apr 30	Oct 22	187
Lawrenceville Intl Airport	429	Apr 8	Apr 22	Oct 26	200
Mattoon Coles County Airport	721	Apr 15	Apr 30	Oct 24	189
Moline Quad City Intl Airport	592	Apr 24	May 9	Oct 18	176
Peoria Gtr Peoria Airport	650	Apr 16	May 4	Oct 23	189
Quincy Regional Airport	769	Apr 14	May 1	Oct 23	191
Rantoul	740	Apr 21	May 6	Oct 18	179
Rockford Gtr Rockford Airport	730	Apr 24	May 8	Oct 17	174
Shabbona 5 NNE	861	Apr 28	May 13	Oct 10	163
Springfield Capital Airport	594	Apr 14	Apr 29	Oct 20	187
West Chicago Dupage Airport	754	Apr 25	May 12	Oct 19	174

All 170 stations in Illinois

Last frost and first frost are medians: a 50% chance of a 32°F night after (spring) or before (fall) that date. 10% risk is the spring date with only a 1-in-10 chance of a later frost. Click a column to sort.

Filter by station name


Albion	530	Apr 4	Apr 20	Oct 28	206
Aledo	730	Apr 22	May 6	Oct 19	181
Alton - Melvin Price L&d	405	Apr 4	Apr 19	Nov 5	214
Altona	765	Apr 28	May 12	Oct 12	165
Anna 2 NNE	640	Apr 8	Apr 26	Oct 29	203
Antioch	750	Apr 23	May 9	Oct 21	179
Athens 4SW	594	Apr 19	May 4	Oct 19	181
Aurora	660	Apr 19	May 4	Oct 23	185
Avon	640	Apr 22	May 8	Oct 19	177
Barrington 3SW	875	Apr 25	May 12	Oct 19	177
Belleville Siu Rsch	450	Apr 12	Apr 28	Oct 20	189
Bentley	650	Apr 13	Apr 30	Oct 22	191
Benton 2 N	445	Apr 4	Apr 21	Oct 28	206
Bloomington 5W	852	Apr 21	May 5	Oct 20	181
Brookport Dam 52	330	Apr 6	Apr 23	Oct 27	203
Brownstown 4 SW	530	Apr 3	Apr 25	Oct 24	202
Cahokia	400	Apr 6	Apr 20	Oct 27	203
Cahokia St Louis Airport	413	Apr 8	Apr 23	Oct 26	200
Cairo 3N	313	Apr 2	Apr 17	Oct 31	211
Carbondale Sewage Plt	390	Apr 9	Apr 25	Oct 22	195
Carbondale Southern Il Airport	406	Apr 9	Apr 25	Oct 22	195
Carlinville	621	Apr 14	Apr 30	Oct 21	188
Carlyle Rsvr	501	Apr 6	Apr 22	Oct 29	204
Carmi 3	335	Apr 15	May 2	Oct 19	183
Casey	620	Apr 14	Apr 30	Oct 20	187
Champaign 3S	721	Apr 15	Apr 29	Oct 24	190
Champaign 9 SW	700	Apr 23	May 9	Oct 13	170
Champaign Willard Airport	754	Apr 19	May 5	Oct 17	180
Channahon Dresden Island Dam	505	Apr 16	May 3	Oct 26	191
Charleston	700	Apr 15	May 3	Oct 23	187
Chenoa	719	Apr 23	May 7	Oct 15	174
Chicago Aurora Municipal Airport	710	Apr 28	May 11	Oct 13	166
Chicago Botanic Garden	630	Apr 26	May 11	Oct 21	176
Chicago Midway Airport	612	Apr 11	Apr 27	Oct 31	201
Chicago Midway Airport 3SW	620	Apr 10	Apr 26	Nov 1	203
Chicago Northerly Island	583	Apr 10	Apr 25	Nov 5	208
Chicago Ohare Intl Airport	658	Apr 16	May 1	Oct 28	193
Chicago Palwaukee Airport	636	Apr 19	May 3	Oct 26	190
Chicago Waukegan Regional Airport	727	Apr 30	May 16	Oct 21	173
Compton 1 NW	905	Apr 27	May 14	Oct 12	167
Congerville 2NW	640	Apr 21	May 7	Oct 17	178
Crystal Lake 4NW	940	Apr 25	May 9	Oct 22	179
Danville	555	Apr 21	May 7	Oct 20	181
De Kalb	873	Apr 24	May 10	Oct 18	177
Decatur Airport	675	Apr 16	Apr 30	Oct 22	187
Decatur Wtp	639	Apr 14	May 1	Oct 24	192
Dixon 1W	660	Apr 21	May 5	Oct 19	180
Dixon Springs Agric Center	527	Apr 14	Apr 30	Oct 21	189
Du Quoin 4 SE	420	Apr 6	Apr 22	Oct 22	199
Dwight	628	Apr 27	May 14	Oct 15	170
Effingham 3SW	625	Apr 13	Apr 29	Oct 24	191
Elgin	763	Apr 26	May 12	Oct 18	174
Elizabeth	675	May 1	May 17	Oct 9	160
Fairfield Radio Wfiw	430	Apr 7	Apr 23	Oct 26	201
Flora	481	Apr 9	Apr 23	Oct 24	198
Flora 5 NW	500	Apr 10	Apr 26	Oct 23	196
Freeport Waste Wtp	750	Apr 26	May 11	Oct 13	169
Fulton L&d #13	592	Apr 13	Apr 28	Oct 26	195
Galena	822	Apr 26	May 11	Oct 15	170
Galesburg	761	Apr 20	May 5	Oct 19	180
Galva	810	Apr 26	May 11	Oct 12	166
Geneseo	639	Apr 20	May 6	Oct 20	180
Gibson City	750	Apr 21	May 5	Oct 17	178
Gladstone Dam 18	538	Apr 8	Apr 23	Oct 29	202
Golden	718	Apr 18	May 1	Oct 21	187
Grand Chain Dam 53	385	Apr 3	Apr 21	Nov 5	216
Grayville	435	Apr 7	Apr 23	Oct 25	201
Harrisburg	365	Apr 7	Apr 25	Oct 26	202
Havana	463	Apr 17	May 3	Oct 19	185
Hennepin	515	Apr 18	May 3	Oct 22	188
Hennepin Wtr Trmt Plt	460	Apr 24	May 10	Oct 17	174
Hillsboro	630	Apr 13	Apr 28	Oct 24	192
Hoopeston	710	Apr 22	May 8	Oct 19	180
Illinois City Dam 16	550	Apr 18	May 2	Oct 24	188
Iuka 12 SW	590	Apr 9	Apr 25	Oct 24	196
Jacksonville 2	626	Apr 17	May 1	Oct 21	186
Jacksonville 2E	610	Apr 19	May 5	Oct 17	179
Jerseyville 2 SW	630	Apr 14	Apr 30	Oct 19	187
Joliet Brandon Rd Dam	543	Apr 19	May 7	Oct 25	188
Kankakee Metro Wastewater	600	Apr 19	May 3	Oct 24	188
Kaskaskia River Navigation Lock	380	Apr 8	Apr 25	Oct 30	202
Kewanee 1 E	780	Apr 24	May 8	Oct 17	175
Knoxville	728	Apr 21	May 6	Oct 20	181
La Harpe	690	Apr 21	May 5	Oct 19	180
Lacon	458	Apr 20	May 7	Oct 17	178
Lake Villa 2NE	840	Apr 24	May 9	Oct 23	180
Lawrenceville 2WSW	451	Apr 12	Apr 30	Oct 25	193
Lawrenceville Intl Airport	429	Apr 8	Apr 22	Oct 26	200
Lincoln	583	Apr 20	May 4	Oct 16	179
Lisle-morton Arboretum	680	Apr 28	May 14	Oct 16	169
Little Red School Hse	715	Apr 19	May 5	Oct 22	183
Marengo	815	Apr 28	May 14	Oct 12	166
Marseilles Lock	490	Apr 27	May 13	Oct 17	171
Mason City 4SE	600	Apr 17	May 4	Oct 18	182
Mattoon	701	Apr 11	Apr 28	Oct 29	199
Mattoon Coles County Airport	721	Apr 15	Apr 30	Oct 24	189
Mc Henry -wg Stratton L&d	736	May 1	May 19	Oct 11	162
McLeansboro	446	Apr 11	Apr 26	Oct 21	190
Minonk	750	Apr 26	May 10	Oct 17	173
Moline Quad City Intl Airport	592	Apr 24	May 9	Oct 18	176
Monmouth	720	Apr 22	May 10	Oct 15	174
Monmouth 4NW	724	Apr 22	May 7	Oct 14	174
Morris 1 NW	524	Apr 20	May 6	Oct 23	184
Morrison	632	Apr 26	May 11	Oct 13	167
Morrisonville	630	Apr 12	Apr 27	Oct 20	190
Mount Carmel	430	Apr 2	Apr 17	Oct 31	209
Mount Carroll	640	May 2	May 18	Oct 7	154
Mount Vernon 3 NE	490	Apr 11	Apr 26	Oct 22	193
Mundelein 4 WSW	840	Apr 29	May 15	Oct 20	172
Nashville 1 E	513	Apr 7	Apr 22	Oct 26	201
Neoga 4NW	643	Apr 16	Apr 29	Oct 20	185
New Boston Dam 17	548	Apr 14	May 2	Oct 24	190
Newton	531	Apr 13	Apr 29	Oct 22	190
Newton 6 SSE	510	Apr 13	Apr 27	Oct 22	191
Normal 4NE	790	Apr 25	May 11	Oct 16	172
Ogden	675	Apr 20	May 7	Oct 21	182
Olney 2S	459	Apr 15	May 3	Oct 23	189
Ottawa 5SW	525	Apr 20	May 5	Oct 22	183
Palestine	450	Apr 12	Apr 26	Oct 22	193
Pana	650	Apr 17	May 3	Oct 23	188
Paris Stp	649	Apr 21	May 9	Oct 20	179
Park Forest	710	Apr 23	May 11	Oct 20	179
Paw Paw 2S	889	Apr 27	May 12	Oct 15	171
Paxton 2 WSW	758	Apr 23	May 9	Oct 12	170
Peoria Gtr Peoria Airport	650	Apr 16	May 4	Oct 23	189
Perry 6 NW	650	Apr 18	May 5	Oct 15	179
Peru	620	Apr 24	May 8	Oct 18	176
Petersburg 1E	600	Apr 13	Apr 28	Oct 21	189
Piper City	670	Apr 25	May 10	Oct 20	175
Pittsfield #2	670	Apr 14	Apr 30	Oct 21	189
Polo 5NW	856	Apr 29	May 14	Oct 7	161
Pontiac	650	Apr 16	May 2	Oct 24	191
Prairie City 2S	650	Apr 17	May 2	Oct 22	185
Princeton	697	Apr 22	May 7	Oct 17	177
Princeville	750	Apr 22	May 6	Oct 14	174
Quincy Dam 21	483	Apr 8	Apr 23	Oct 30	204
Quincy Regional Airport	769	Apr 14	May 1	Oct 23	191
Ramsey	600	Apr 15	May 1	Oct 19	185
Rantoul	740	Apr 21	May 6	Oct 18	179
Rend Lake Dam	455	Apr 4	Apr 19	Oct 27	204
Robinson	535	Apr 13	Apr 28	Oct 22	190
Rochelle	775	Apr 26	May 12	Oct 13	168
Rock Island L&d 15	568	Apr 19	May 4	Oct 22	184
Rockford Gtr Rockford Airport	730	Apr 24	May 8	Oct 17	174
Romeoville WFO	660	Apr 20	May 6	Oct 22	184
Rosiclare 5NW	400	Apr 19	May 8	Oct 20	181
Rushville	673	Apr 16	May 3	Oct 23	189
Salem	550	Apr 9	Apr 23	Oct 26	197
Shabbona 5 NNE	861	Apr 28	May 13	Oct 10	163
Shelbyville Dam	650	Apr 10	Apr 28	Oct 24	195
Sidell 4N	672	Apr 19	May 3	Oct 19	181
Smithland L&d	357	Apr 3	Apr 21	Oct 30	207
Sparta 1 W	535	Apr 12	Apr 29	Oct 22	191
Springfield #2	599	Apr 15	Apr 30	Oct 22	188
Springfield Capital Airport	594	Apr 14	Apr 29	Oct 20	187
Stockton 3 NNE	970	Apr 27	May 12	Oct 9	165
Streamwood	819	Apr 30	May 16	Oct 13	163
Streator 3 SE	610	Apr 12	Apr 25	Oct 28	199
Sullivan 3S	640	Apr 15	Apr 30	Oct 22	187
Tuscola	651	Apr 15	May 1	Oct 20	188
Vandalia	490	Apr 10	Apr 24	Oct 24	196
Virden	675	Apr 7	Apr 21	Oct 29	205
Walnut	671	Apr 24	May 9	Oct 14	172
Watseka 2 NW	620	Apr 24	May 10	Oct 16	174
Waukegan	700	Apr 30	May 14	Oct 19	170
West Chicago Dupage Airport	754	Apr 25	May 12	Oct 19	174
Wheaton 3 SE	680	Apr 27	May 14	Oct 17	173
White Hall 1 E	580	Apr 13	Apr 28	Oct 22	190
Winchester	551	Apr 18	May 5	Oct 20	183
Windsor	690	Apr 16	Apr 30	Oct 22	187

Frequently asked questions

When is the last frost in Illinois?

The median last spring frost (32°F) across Illinois's NOAA weather stations is April 18, based on 1991–2020 climate normals. It ranges from April 2 at Cairo 3N to May 2 at Mount Carroll. For a safer planting date, use the 10%-risk date; the state median for that is May 3.

When is the first frost in Illinois?

The median first fall frost across Illinois's stations is October 21. The earliest median first frost is October 7 at Mount Carroll, and the latest is November 5 at Grand Chain Dam 53.

How long is the growing season in Illinois?

The median frost-free season is 185 days across Illinois's stations, from 154 days at Mount Carroll to 216 days at Grand Chain Dam 53.

When should I plant tomatoes in Illinois?

Plant tomatoes outdoors after your local last frost, ideally after the 10%-risk date when nights stay above 50°F. At a typical Illinois station that means starting seeds indoors 6–8 weeks before April 18 and transplanting from about May 3. Check your ZIP code, because dates vary by weeks across the state.

How to use these dates

Frost dates are 30-year averages from NOAA, not forecasts. Use them to plan seed starting and planting, then watch the 10-day forecast as the date approaches. Cold air settles in valleys and low spots, so a garden at the bottom of a slope can frost a week or more later in spring than the nearest station shows.

Ready to plan? The planting calendar by ZIP code turns these dates into start-indoors, transplant and sowing dates for 30 crops.

Sources and method

Dates are the 32°F freeze probabilities published in the NOAA NCEI 1991–2020 U.S. Climate Normals for each station. Station names are NOAA's, lightly expanded for readability. See the methodology or download the full table.