Illinois Weather Records
Weather data and records for the U.S. state of Illinois based on data compiled by the NOAA.
All data displayed in U.S. customary units.
All data displayed in metric units.
Illinois Statewide Averages
Average temperatures over the entire territory of the state, from 1991–2020.
| Month |
High (°F°C) |
Low (°F°C) |
| January |
34.71.5 |
18.6-7.4 |
| February |
39.74.3 |
22.4-5.3 |
| March |
51.310.7 |
31.5-0.3 |
| April |
63.917.7 |
41.35.1 |
| May |
74.123.4 |
52.411.3 |
| June |
82.928.3 |
61.516.4 |
| July |
85.829.9 |
65.118.4 |
| August |
84.429.1 |
62.817.1 |
| September |
78.525.8 |
55.012.8 |
| October |
66.119.0 |
43.56.4 |
| November |
51.310.7 |
33.00.5 |
| December |
39.44.1 |
23.7-4.6 |
| Entire Year |
62.817.1 |
42.75.9 |
Illinois Cities
Yearly weather averages for various places in Illinois, from 1991–2020.
| Average (°F°C) |
Record (°F°C) |
Yearly (inchescm) |
| Aledo |
59.815.5 |
39.34.1 |
113.045.0 |
-33.0-36.1 |
36.592.7 |
21.354.2 |
| Aurora |
60.015.6 |
40.24.5 |
111.043.9 |
-26.0-32.2 |
39.199.4 |
31.279.3 |
| Belleville |
68.720.4 |
46.78.2 |
109.943.3 |
-27.0-32.8 |
42.9108.9 |
11.629.4 |
| Bloomington-Normal |
62.016.7 |
40.44.7 |
114.145.6 |
-24.0-31.1 |
38.998.9 |
20.953.1 |
| Carbondale |
66.919.4 |
45.27.4 |
113.045.0 |
-25.1-31.7 |
48.4122.8 |
11.328.6 |
| Carlyle |
65.018.3 |
45.37.4 |
113.045.0 |
-22.0-30.0 |
44.5113.0 |
n/a |
| Champaign |
62.316.8 |
42.65.9 |
109.042.8 |
-25.1-31.7 |
40.7103.4 |
20.752.5 |
| Charleston |
64.818.2 |
44.87.1 |
109.943.3 |
-27.0-32.8 |
43.6110.8 |
20.652.4 |
| Chicago |
60.215.7 |
44.06.7 |
106.041.1 |
-25.1-31.7 |
40.9103.8 |
39.4100.1 |
| Danville |
63.117.3 |
43.16.2 |
111.944.4 |
-26.0-32.2 |
42.4107.6 |
13.032.9 |
| Decatur |
63.617.6 |
44.26.8 |
113.045.0 |
-25.1-31.7 |
39.8101.1 |
14.737.2 |
| Dixon |
59.115.1 |
39.64.2 |
109.943.3 |
-32.1-35.6 |
40.2102.0 |
34.186.5 |
| Du Quoin |
66.819.4 |
46.58.1 |
113.045.0 |
-22.0-30.0 |
46.9119.0 |
11.027.8 |
| Elgin |
58.914.9 |
39.24.0 |
102.939.4 |
-27.0-32.8 |
39.399.9 |
31.780.6 |
| Fairfield |
66.619.2 |
45.27.4 |
113.045.0 |
-23.1-30.6 |
45.5115.6 |
13.634.5 |
| Freeport |
58.014.5 |
38.03.3 |
111.944.4 |
-31.0-35.0 |
38.397.4 |
32.883.2 |
| Galesburg |
60.215.6 |
41.65.3 |
111.944.4 |
-27.9-33.3 |
38.898.6 |
23.660.1 |
| Geneseo |
60.615.9 |
41.75.4 |
107.141.7 |
-25.1-31.7 |
38.998.8 |
27.971.0 |
| Hoopeston |
62.216.8 |
42.86.0 |
111.043.9 |
-25.1-31.7 |
40.5102.8 |
17.845.2 |
| Jacksonville |
64.017.8 |
41.35.2 |
114.145.6 |
-27.9-33.3 |
39.099.0 |
18.446.8 |
| Joliet |
60.015.6 |
41.25.1 |
104.040.0 |
-26.0-32.2 |
37.094.0 |
16.742.4 |
| Kankakee |
61.516.4 |
41.25.1 |
109.042.8 |
-29.0-33.9 |
37.896.0 |
20.552.2 |
| Kewanee |
59.215.1 |
39.03.9 |
105.140.6 |
-27.0-32.8 |
39.099.0 |
30.076.3 |
| Lincoln |
62.817.1 |
41.45.2 |
113.045.0 |
-34.1-36.7 |
39.099.1 |
19.349.1 |
| Moline |
61.216.2 |
41.05.0 |
104.040.0 |
-32.8-36.0 |
38.397.2 |
36.191.8 |
| Monmouth |
62.016.7 |
41.25.1 |
109.943.3 |
-27.0-32.8 |
38.898.6 |
25.163.6 |
| Morris |
60.715.9 |
41.55.3 |
109.042.8 |
-26.0-32.2 |
39.099.0 |
25.965.9 |
| Morrison |
60.315.7 |
38.23.4 |
111.944.4 |
-35.0-37.2 |
39.199.4 |
32.281.8 |
| Mt. Vernon |
64.217.9 |
44.77.1 |
114.145.6 |
-22.0-30.0 |
45.0114.4 |
11.328.6 |
| Olney |
65.318.5 |
44.56.9 |
111.944.4 |
-25.1-31.7 |
47.8121.3 |
11.629.4 |
| Ottawa |
61.116.2 |
40.94.9 |
111.944.4 |
-26.0-32.2 |
35.189.1 |
22.557.2 |
| Pana |
64.918.3 |
43.66.4 |
115.046.1 |
-25.1-31.7 |
42.7108.4 |
15.840.1 |
| Paris |
62.516.9 |
43.06.1 |
109.042.8 |
-23.1-30.6 |
42.5108.0 |
18.847.8 |
| Peoria |
61.916.6 |
42.96.0 |
105.140.6 |
-25.1-31.7 |
37.595.4 |
26.066.1 |
| Quincy |
62.617.0 |
43.76.5 |
114.145.6 |
-29.0-33.9 |
36.292.1 |
n/a |
| Rantoul |
63.317.4 |
41.25.1 |
109.042.8 |
-27.0-32.8 |
39.4100.0 |
10.927.7 |
| Rockford |
59.015.0 |
39.54.2 |
111.944.4 |
-30.8-34.9 |
37.294.6 |
38.096.4 |
| Springfield |
63.717.6 |
43.76.5 |
111.944.4 |
-24.0-31.1 |
38.096.6 |
21.654.9 |
| Tuscola |
63.117.3 |
43.26.2 |
113.045.0 |
-26.0-32.2 |
40.9103.9 |
18.045.7 |