Illinois Weather Records

Weather averages and records for the U.S. state of Illinois based on data made available by the NOAA.

State:

Month:

Illinois Statewide Averages

Average temperatures and precipitation over the entire territory of the state, from 1991–2020.

Month	High (°F)	Low (°F)	Precipitation (in)
January	34.7	18.6	2.3
February	39.7	22.4	2.1
March	51.3	31.5	2.9
April	63.9	41.3	4.2
May	74.1	52.4	4.8
June	82.9	61.5	4.7
July	85.8	65.1	4.1
August	84.4	62.8	3.6
September	78.5	55.0	3.4
October	66.1	43.5	3.3
November	51.3	33.0	3.1
December	39.4	23.7	2.4
Entire Year	62.7	42.6	40.7

Hottest Temperature All-Time

The highest recorded temperature in Illinois history was 117 °F, which was reached in East Saint Louis on July 14, 1954.

Coldest Temperature All-Time

The lowest temperature in Illinois history was -38 °F, which was recorded in Mt. Caroll on Jan 31, 2019.

Illinois Cities

Yearly weather averages for various places in Illinois, from 1991–2020.

City	Average (°F)		Record (°F)		Yearly (inches)
City	High	Low	High	Low	Precipitation	Snow
Aledo	59.8	39.3	113	-33	38.4	21.9
Aurora	60.0	40.2	111	-26	39.1	31.4
Belleville	68.7	46.7	110	-27	42.9	11.0
Bloomington-Normal	62.0	40.4	114	-24	39.0	20.9
Carbondale	66.9	45.2	113	-25	48.4	11.3
Carlyle	65.0	45.3	113	-22	44.2	n/a
Champaign	62.4	42.1	109	-25	37.9	n/a
Charleston	64.8	44.8	110	-27	43.7	20.1
Chicago	60.2	44.0	106	-25	40.8	39.3
Danville	63.1	43.1	112	-26	42.4	13.0
Decatur	63.6	44.2	113	-25	39.9	15.2
Dixon	59.1	39.6	110	-32	40.2	34.1
Du Quoin	66.8	46.5	113	-22	47.1	11.0
Elgin	58.8	39.2	103	-27	39.3	31.8
Elizabeth	58.1	36.1	103	-35	39.6	31.2
Fairfield	66.6	45.2	113	-23	45.5	13.6
Freeport	58.0	38.0	112	-31	38.4	32.8
Galesburg	60.2	41.6	112	-28	38.8	23.6
Geneseo	60.6	41.7	107	-25	38.9	28.0
Hoopeston	62.2	42.8	111	-25	40.6	17.9
Jacksonville	64.0	41.3	114	-28	39.0	18.4
Joliet	60.0	41.2	104	-26	37.1	16.7
Kankakee	61.5	41.2	109	-29	37.5	20.9
Kewanee	59.2	39.0	105	-27	39.0	30.0
Lincoln	62.8	41.4	113	-34	39.1	18.7
Moline	61.2	41.0	111	-33	38.2	36.1
Monmouth	62.0	41.2	110	-27	39.5	25.6
Morris	60.7	41.5	109	-26	39.0	25.9
Morrison	60.3	38.2	112	-35	39.2	32.2
Mt. Vernon	64.6	44.6	114	-22	43.6	11.3
Olney	65.3	44.5	112	-25	47.7	11.6
Ottawa	61.1	40.9	112	-26	35.2	23.1
Pana	64.9	43.6	115	-25	42.7	15.1
Paris	62.5	43.0	109	-23	42.8	18.8
Peoria	61.9	42.9	113	-26	37.5	26.0
Quincy	62.6	43.7	114	-29	36.2	n/a
Rantoul	63.3	41.2	109	-27	39.4	10.5
Rockford	59.0	39.5	112	-31	37.2	37.9
Springfield	63.7	43.7	112	-24	38.0	21.6
Tuscola	63.1	43.2	113	-26	41.0	18.0