# Counties in Illinois by average annual temperature, 2025

All 102 values come from NOAA National Centers for Environmental Information for 2025, so the places are comparable.

- Indicator id: `average_temperature_annual`
- Unit: °F
- Definition: Mean air temperature from January to December, in degrees Fahrenheit: the average of the 12 monthly mean temperatures. NOAA computes it from its climate divisional dataset (nClimDiv): station readings interpolated onto a 5 km grid and averaged over the area.
- Source: NOAA National Centers for Environmental Information, NOAA Climate at a Glance, January to December average temperature, counties (https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping)
- Publisher page: https://invokely.ai/en/publishers/noaa-ncei
- Retrieved: 2026-10-12
- Citation: NOAA National Centers for Environmental Information, Climate at a Glance. NOAA Climate at a Glance, January to December average temperature, counties. From the NOAA Monthly U.S. Climate Divisional Database (nClimDiv), doi:10.7289/V5M32STR. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping. Retrieved 2026-10-12.
- Web page: https://invokely.ai/rankings/average-annual-temperature/illinois-counties

| Rank | Place | °F |
|---:|---|---:|
| 1 | Alexander County | 58.7 |
| 1 | Pulaski County | 58.7 |
| 3 | Massac County | 58.6 |
| 4 | Hardin County | 57.8 |
| 5 | Pope County | 57.7 |
| 6 | Gallatin County | 57.4 |
| 6 | Johnson County | 57.4 |
| 8 | Union County | 57.3 |
| 9 | Monroe County | 57.2 |
| 9 | White County | 57.2 |
| 11 | Franklin County | 57.1 |
| 11 | Jackson County | 57.1 |
| 11 | Perry County | 57.1 |
| 11 | Saline County | 57.1 |
| 15 | Jefferson County | 57 |
| 15 | Williamson County | 57 |
| 17 | Hamilton County | 56.9 |
| 17 | Randolph County | 56.9 |
| 17 | St. Clair County | 56.9 |
| 17 | Wabash County | 56.9 |
| 21 | Edwards County | 56.8 |
| 21 | Washington County | 56.8 |
| 23 | Clinton County | 56.6 |
| 23 | Wayne County | 56.6 |
| 25 | Marion County | 56.2 |
| 26 | Lawrence County | 56.1 |
| 26 | Richland County | 56.1 |
| 28 | Clay County | 56 |
| 28 | Madison County | 56 |
| 30 | Jersey County | 55.8 |
| 31 | Bond County | 55.7 |
| 31 | Calhoun County | 55.7 |
| 33 | Crawford County | 55.6 |
| 33 | Jasper County | 55.6 |
| 35 | Fayette County | 55.4 |
| 36 | Effingham County | 55.2 |
| 37 | Greene County | 55.1 |
| 38 | Clark County | 54.8 |
| 38 | Cumberland County | 54.8 |
| 40 | Macoupin County | 54.7 |
| 40 | Pike County | 54.7 |
| 42 | Montgomery County | 54.6 |
| 42 | Scott County | 54.6 |
| 44 | Shelby County | 54.3 |
| 45 | Coles County | 54.2 |
| 46 | Adams County | 54.1 |
| 46 | Christian County | 54.1 |
| 46 | Morgan County | 54.1 |
| 49 | Cass County | 53.9 |
| 49 | Douglas County | 53.9 |
| 51 | Brown County | 53.8 |
| 51 | Moultrie County | 53.8 |
| 53 | Edgar County | 53.7 |
| 54 | Mason County | 53.6 |
| 54 | Sangamon County | 53.6 |
| 56 | Schuyler County | 53.5 |
| 57 | Fulton County | 53.4 |
| 57 | Macon County | 53.4 |
| 57 | Piatt County | 53.4 |
| 57 | Tazewell County | 53.4 |
| 61 | Champaign County | 53.2 |
| 61 | Hancock County | 53.2 |
| 61 | Menard County | 53.2 |
| 61 | Peoria County | 53.2 |
| 65 | Logan County | 53.1 |
| 66 | De Witt County | 53 |
| 67 | McLean County | 52.8 |
| 68 | McDonough County | 52.7 |
| 68 | Woodford County | 52.7 |
| 70 | Henderson County | 52.6 |
| 70 | Vermilion County | 52.6 |
| 72 | Marshall County | 52.3 |
| 73 | Ford County | 52.2 |
| 73 | Knox County | 52.2 |
| 73 | Livingston County | 52.2 |
| 73 | Warren County | 52.2 |
| 77 | Mercer County | 52.1 |
| 77 | Stark County | 52.1 |
| 79 | Iroquois County | 51.7 |
| 79 | Putnam County | 51.7 |
| 79 | Rock Island County | 51.7 |
| 82 | Grundy County | 51.6 |
| 82 | Henry County | 51.6 |
| 84 | Kankakee County | 51.5 |
| 85 | Bureau County | 51.3 |
| 85 | Will County | 51.3 |
| 87 | Cook County | 51.2 |
| 87 | Whiteside County | 51.2 |
| 89 | Kendall County | 51.1 |
| 90 | LaSalle County | 51 |
| 91 | DuPage County | 50.9 |
| 92 | Lee County | 50.6 |
| 93 | Kane County | 50.3 |
| 94 | DeKalb County | 50 |
| 94 | Lake County | 50 |
| 96 | Carroll County | 49.9 |
| 96 | Ogle County | 49.9 |
| 98 | Winnebago County | 49.6 |
| 99 | Boone County | 49.4 |
| 100 | McHenry County | 49.1 |
| 101 | Jo Daviess County | 49 |
| 102 | Stephenson County | 48.8 |