Illinois weather in December: Statewide normals and every place, NOAA 1991-2020
In December, Illinois's statewide normal high is 39°F and normal low 24°F; normal highs run from 33°F in Galena to 48°F in Anna (NOAA 1991-2020 normals).
- Statewide normal high
- 39°FDecember, 1991-2020
- Statewide normal low
- 24°FDecember, 1991-2020
- Statewide normal precipitation
- 2.43 inDecember
- Warmest place
- 48°Fnormal high, Anna
- Coolest place
- 33°Fnormal high, Galena
Where is Illinois warmest and wettest in December?
Anna has the warmest December afternoons (48°F) and Galena the coolest (33°F). Rosiclare gets the most precipitation (4.44 in) and Wheeling the least (1.64 in). The most snow falls in Mundelein (9.7 inches).
Statewide, December averaged 40.2°F in 2021, 30.3°F in 2022, 39.6°F in 2023, 34.0°F in 2024, 29.8°F in 2025, against a 1991-2020 normal of 31.6°F.
| Place | High | Low | Precip. | Snow |
|---|---|---|---|---|
| Chicago | 37°F | 24°F | 2.11 | 7.6 |
| Aurora | 36°F | 22°F | 2.19 | 6.4 |
| Joliet | 36°F | 22°F | 1.94 | 3.2 |
| Rockford | 34°F | 20°F | 1.93 | 9.4 |
| Elgin | 36°F | 20°F | 2.22 | 8.7 |
| Springfield | 41°F | 25°F | 2.15 | 4.3 |
| Peoria | 39°F | 23°F | 2.21 | 6.2 |
| Champaign | 39°F | 24°F | 2.14 | – |
| Waukegan | 36°F | 22°F | – | – |
| Bloomington | 35°F | 21°F | 2.28 | – |
| Decatur | 40°F | 25°F | 2.12 | – |
| Wheaton | 38°F | 23°F | 2.22 | 4.2 |
| Normal | 38°F | 21°F | 2.30 | 3.6 |
| Moline | 37°F | 21°F | 2.04 | 8.8 |
| Crystal Lake | 36°F | 20°F | 2.10 | 8.7 |
| Romeoville | 37°F | 22°F | 2.15 | 7.5 |
| Belleville | 46°F | 28°F | 2.61 | 2.9 |
| DeKalb | 34°F | 19°F | 2.04 | 6.6 |
| Quincy | 39°F | 24°F | 1.80 | – |
| Streamwood | 38°F | 19°F | 1.92 | 8.7 |
| Wheeling | 37°F | 24°F | 1.64 | – |
| Rock Island | 36°F | 20°F | 2.02 | – |
| Mundelein | 34°F | 20°F | 2.12 | 9.7 |
| Galesburg | 35°F | 20°F | 2.14 | 5.9 |
| Burbank | 38°F | 25°F | 2.33 | 7.9 |
| Danville | 40°F | 25°F | 2.73 | – |
| West Chicago | 35°F | 21°F | 1.67 | – |
| Alton | 44°F | 27°F | 2.59 | – |
| Lisle | 37°F | 21°F | 2.32 | – |
| Kankakee | 38°F | 22°F | 2.35 | 5.3 |
| Freeport | 33°F | 18°F | 1.83 | 8.9 |
| Carbondale | 46°F | 28°F | 3.12 | – |
| Park Forest | 36°F | 22°F | 2.47 | 4.0 |
| Ottawa | 36°F | 21°F | 1.99 | 4.8 |
| Jacksonville | 40°F | 23°F | 2.35 | – |
| Charleston | 42°F | 26°F | 2.79 | 3.0 |
| Cahokia Heights | 44°F | 29°F | 2.32 | – |
| Mattoon | 40°F | 26°F | 1.84 | – |
| Dixon | 35°F | 20°F | 2.17 | 5.6 |
| Antioch | 35°F | 21°F | – | – |
| Morris | 37°F | 22°F | 2.02 | 5.3 |
| Channahon | 37°F | 23°F | 1.96 | 6.1 |
| Mount Vernon | 43°F | 26°F | 2.89 | 2.5 |
| Lincoln | 39°F | 23°F | 2.29 | 4.9 |
| Effingham | 42°F | 25°F | 2.77 | 2.4 |
| Streator | 37°F | 22°F | 2.17 | 6.8 |
| Rantoul | 40°F | 22°F | 2.21 | – |
| Kewanee | 36°F | 20°F | 2.17 | 7.5 |
| Pontiac | 38°F | 23°F | 2.13 | 5.7 |
| Barrington | 34°F | 20°F | 2.19 | 9.6 |
| Peru | 36°F | 20°F | 2.10 | 8.7 |
| Rochelle | 34°F | 18°F | 1.95 | – |
| Lake Villa | 35°F | 21°F | 2.28 | 9.2 |
| Monmouth | 37°F | 21°F | 2.15 | 4.8 |
| Olney | 42°F | 26°F | 3.50 | 2.7 |
| Jerseyville | 41°F | 24°F | 2.65 | 2.2 |
| Paris | 39°F | 23°F | 2.85 | 4.0 |
| Harrisburg | 47°F | 29°F | 3.38 | – |
| Marengo | 35°F | 19°F | 1.94 | 9.3 |
| Princeton | 35°F | 20°F | 2.24 | 6.8 |
| Vandalia | 42°F | 26°F | 2.69 | – |
| Robinson | 42°F | 25°F | 3.15 | – |
| Salem | 43°F | 26°F | 2.93 | 2.9 |
| Mount Carmel | 44°F | 28°F | 3.45 | 2.8 |
| Benton | 44°F | 28°F | – | – |
| Geneseo | 36°F | 21°F | 2.12 | 7.3 |
| Hillsboro | 43°F | 26°F | 2.62 | – |
| Du Quoin | 44°F | 28°F | 3.24 | 3.6 |
| Carlinville | 41°F | 25°F | 2.32 | 2.8 |
| Pana | 42°F | 25°F | 2.26 | 2.7 |
| Fairfield | 45°F | 29°F | 3.30 | – |
| Marseilles | 37°F | 21°F | 2.11 | 5.3 |
| Hoopeston | 38°F | 24°F | 2.12 | 5.3 |
| Carmi | 45°F | 25°F | 3.90 | 2.1 |
| Tuscola | 39°F | 24°F | 2.53 | 3.7 |
| Flora | 43°F | 26°F | 3.26 | 4.5 |
| Shelbyville | 41°F | 25°F | 2.59 | – |
| Watseka | 38°F | 21°F | 2.10 | 4.4 |
| Paxton | 37°F | 21°F | 2.17 | 4.2 |
| Lawrenceville | 43°F | 27°F | 2.66 | – |
| Sullivan | 40°F | 25°F | 2.75 | 3.7 |
| Anna | 48°F | 30°F | 4.10 | 2.6 |
| Pittsfield | 42°F | 24°F | 2.33 | 3.4 |
| Sparta | 44°F | 26°F | 2.70 | 2.6 |
| Dwight | 36°F | 20°F | 1.95 | 5.6 |
| Morrison | 35°F | 18°F | 2.02 | 6.3 |
| Fulton | 35°F | 21°F | 1.69 | – |
| Aledo | 36°F | 20°F | 2.01 | 4.1 |
| Gibson City | 37°F | 22°F | 2.18 | 4.6 |
| Carlyle | 43°F | 26°F | 3.10 | – |
| Galena | 33°F | 17°F | 1.82 | 9.5 |
| Virden | 41°F | 26°F | 2.41 | 3.3 |
| Nashville | 43°F | 26°F | 2.67 | 2.5 |
| Rushville | 39°F | 23°F | 2.41 | – |
| Knoxville | 36°F | 21°F | 2.17 | 5.9 |
| Havana | 39°F | 22°F | 2.35 | 6.9 |
| Newton | 42°F | 27°F | 3.14 | 3.8 |
| McLeansboro | 45°F | 26°F | 3.50 | 3.4 |
| Galva | 36°F | 19°F | 2.01 | – |
| Casey | 42°F | 24°F | 3.06 | 3.2 |
| Polo | 35°F | 19°F | 2.14 | – |
| White Hall | 41°F | 24°F | 2.33 | 3.7 |
| Petersburg | 39°F | 23°F | 1.93 | 4.0 |
| Mason City | 38°F | 22°F | 1.70 | 2.6 |
| Athens | 40°F | 23°F | 2.33 | – |
| Minonk | 38°F | 21°F | 2.21 | 5.5 |
| Albion | 44°F | 27°F | – | – |
| Lacon | 38°F | 23°F | 2.17 | 5.2 |
| Princeville | 37°F | 20°F | 2.05 | 6.4 |
| Chenoa | 37°F | 21°F | 2.03 | 5.4 |
| Stockton | 33°F | 18°F | 1.69 | 8.0 |
| Cairo | 47°F | 30°F | 4.25 | – |
| Winchester | 41°F | 23°F | 2.43 | – |
| Grayville | 45°F | 28°F | 3.77 | 4.7 |
| Mount Carroll | 36°F | 17°F | 2.21 | 8.8 |
| Neoga | 42°F | 25°F | 2.82 | – |
| Walnut | 35°F | 19°F | 1.99 | 7.3 |
| Palestine | 42°F | 28°F | 3.06 | 3.4 |
| La Harpe | 37°F | 21°F | 2.05 | – |
| Windsor | 39°F | 25°F | 2.45 | 2.6 |
| Morrisonville | 41°F | 25°F | 2.22 | 3.2 |
| Rosiclare | 45°F | 26°F | 4.44 | 0.6 |
| Ramsey | 40°F | 24°F | 2.68 | 2.4 |
| Shabbona | 33°F | 19°F | 2.05 | – |
| Paw Paw | 33°F | 18°F | 1.93 | 7.5 |
| Hennepin | 37°F | 22°F | 2.19 | – |
| Piper City | 40°F | 22°F | 3.01 | 6.2 |
| Ogden | 39°F | 24°F | 2.35 | 5.5 |
| Brookport | 47°F | 29°F | 4.05 | 0.5 |
| Elizabeth | 34°F | 17°F | 1.89 | 6.9 |
| Brownstown | 42°F | 27°F | 2.15 | – |
| Avon | 36°F | 20°F | 1.86 | 5.8 |
| Golden | 39°F | 22°F | – | – |
| New Boston | 37°F | 22°F | 1.77 | – |
| Congerville | 39°F | 23°F | 2.04 | 5.2 |
| Sidell | 38°F | 23°F | 2.48 | 6.0 |
| Altona | 35°F | 19°F | 2.10 | – |
| Prairie City | 38°F | 22°F | 1.80 | 5.0 |
| Perry | 41°F | 23°F | 2.26 | 5.1 |
| Compton | 34°F | 19°F | – | – |
| Gladstone | 37°F | 22°F | 1.81 | 3.2 |
| Bentley | 39°F | 24°F | 1.89 | 5.2 |
| Kaskaskia | 44°F | 28°F | 2.85 | 0.9 |
| Illinois City | 36°F | 20°F | 1.68 | – |
| Cahokia | 45°F | 27°F | 2.75 | 2.9 |
| Chicago Aurora Municipal Airport | 36°F | 21°F | 1.68 | – |
| Chicago Botanic Garden | 38°F | 22°F | 2.34 | 5.9 |
| Chicago Midway Airport | 38°F | 25°F | 1.79 | – |
| Chicago Waukegan Regional Airport | 36°F | 22°F | 1.86 | – |
| Dixon Springs Agricultural Center | 46°F | 29°F | 4.16 | 1.4 |
| Grand Chain Dam 53 | 47°F | 31°F | 4.24 | 1.8 |
| Iuka (12 mi SW) | 43°F | 26°F | 3.02 | 3.2 |
| Little Red School House | 38°F | 21°F | 2.40 | – |
| McHenry W.G. Stratton Lock and Dam | 36°F | 19°F | 1.94 | 8.2 |
| Rend Lake Dam | 44°F | 27°F | 2.89 | – |
| Smithland Lock and Dam | 46°F | 29°F | 4.35 | 1.8 |
Source: NOAA NCEI nClimDiv statewide normals; NOAA NCEI 1991-2020 monthly normals for each station.