Counties in Illinois by average annual temperature

Alexander County had the highest average annual temperature of 102 counties in 2022, at 57.7 °F. Jo Daviess County had the lowest, at 47.1 °F. The median was 52.2 °F and the figure for Illinois was 52.1 °F. Source: NOAA National Centers for Environmental Information.

Highest57.7Alexander County

Lowest47.1Jo Daviess County

Median52.2102 counties

Illinois52.1History

Top 40 counties, 2022

°F. Source: NOAA NCEI, NOAA Climate at a Glance, January to December average temperature, counties. Retrieved 2026-10-12.

Full ranking

Rank	Counties	2022 °F	Change on 2021
1	Alexander County	57.7	-1.7%
1	Massac County	57.7	-1.4%
1	Pulaski County	57.7	-1.9%
4	Hardin County	56.9	-0.9%
5	Pope County	56.8	-1%
6	Gallatin County	56.6	-0.7%
7	Johnson County	56.5	-1.6%
7	Union County	56.5	-2.1%
9	Monroe County	56.3	-2.1%
9	White County	56.3	-0.9%
11	Saline County	56.1	-1.2%
12	Hamilton County	56	-1.8%
13	Franklin County	55.8	-2.1%
13	Jackson County	55.8	-2.3%
15	Perry County	55.7	-1.9%
15	Randolph County	55.7	-1.9%
15	St. Clair County	55.7	-1.9%
15	Wayne County	55.7	-2.3%
15	Williamson County	55.7	-2.1%
20	Edwards County	55.6	-2.1%
20	Jefferson County	55.6	-2.3%
22	Wabash County	55.4	-2.1%
22	Washington County	55.4	-2.1%
24	Clinton County	55.2	-2.3%
25	Madison County	54.8	-2.5%
25	Richland County	54.8	-2.3%
27	Clay County	54.7	-2.3%
27	Marion County	54.7	-2.5%
29	Lawrence County	54.6	-2.3%
30	Jersey County	54.5	-2.9%
31	Bond County	54.3	-2.7%
32	Calhoun County	54.2	-2.7%
32	Crawford County	54.2	-2%
34	Jasper County	54.1	-2.3%
35	Fayette County	53.7	-2.7%
36	Clark County	53.6	-2.4%
36	Effingham County	53.6	-2.5%
38	Greene County	53.5	-3.1%
38	Macoupin County	53.5	-2.7%
40	Cumberland County	53.4	-2.6%
41	Montgomery County	53.2	-2.7%
42	Coles County	52.8	-2.9%
43	Pike County	52.7	-3.1%
44	Christian County	52.6	-2.8%
44	Shelby County	52.6	-2.8%
46	Scott County	52.5	-3.5%
47	Douglas County	52.4	-3.3%
47	Edgar County	52.4	-3%
47	Moultrie County	52.4	-3%
50	Sangamon County	52.3	-3%
51	Adams County	52.2	-3.3%
51	Macon County	52.2	-3%
51	Morgan County	52.2	-3.3%
54	Mason County	52.1	-3.5%
55	Cass County	51.9	-3.4%
55	Logan County	51.9	-3.7%
55	Menard County	51.9	-3.4%
55	Piatt County	51.9	-3.2%
59	Tazewell County	51.8	-3.5%
60	Brown County	51.6	-3.6%
60	De Witt County	51.6	-3.4%
62	Champaign County	51.4	-3.4%
62	Fulton County	51.4	-3.6%
62	Hancock County	51.4	-3.4%
62	Schuyler County	51.4	-3.6%
66	Peoria County	51.3	-3.6%
67	McLean County	51.2	-3.6%
67	Vermilion County	51.2	-3%
69	Woodford County	51	-3.6%
70	Livingston County	50.7	-4.2%
70	McDonough County	50.7	-3.8%
72	Ford County	50.5	-3.8%
73	Henderson County	50.4	-4%
73	Iroquois County	50.4	-3.4%
73	Marshall County	50.4	-4%
76	Cook County	50.3	-3.6%
77	Kankakee County	50.1	-3.7%
78	Grundy County	50	-4.2%
78	Putnam County	50	-4%
80	Mercer County	49.9	-3.9%
80	Rock Island County	49.9	-3.9%
82	Will County	49.8	-4%
83	Knox County	49.7	-3.9%
83	Warren County	49.7	-3.9%
85	DuPage County	49.6	-4.1%
85	Stark County	49.6	-4.1%
87	LaSalle County	49.4	-4.3%
88	Henry County	49.3	-4.1%
89	Bureau County	49.2	-4.3%
89	Kendall County	49.2	-4.5%
91	Whiteside County	49.1	-4.1%
92	Lake County	48.9	-4.1%
93	Kane County	48.5	-4.5%
93	Lee County	48.5	-4.3%
95	Ogle County	48.3	-4.5%
96	Winnebago County	48.2	-4.7%
97	Boone County	48.1	-4.8%
97	McHenry County	48.1	-4.4%
99	Carroll County	48	-4.2%
99	DeKalb County	48	-5%
101	Stephenson County	47.4	-4%
102	Jo Daviess County	47.1	-4.7%

Other periods

About this ranking

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.

Values are area averages, so a county with mountains and valleys has one value for very different local climates. NOAA revises the last two years every month.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

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.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

NOAA National Centers for Environmental Information. (2026). NOAA Climate at a Glance, January to December average temperature, counties (Counties in Illinois by average annual temperature, 2022) [Data set]. Retrieved October 12, 2026, from https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping

MLA 9

NOAA Climate at a Glance, January to December average temperature, counties, Counties in Illinois by average annual temperature, 2022. NOAA National Centers for Environmental Information, 6 Oct. 2026, https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping. Invokely, https://invokely.ai/rankings/average-annual-temperature/illinois-counties?period=2022. Accessed 12 Oct. 2026.

Chicago (author-date)

NOAA National Centers for Environmental Information. 2026. NOAA Climate at a Glance, January to December average temperature, counties. Counties in Illinois by average annual temperature, 2022. Dataset. Accessed October 12, 2026. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping. Also distributed by Invokely, https://invokely.ai/rankings/average-annual-temperature/illinois-counties?period=2022.

Harvard

NOAA National Centers for Environmental Information (2026) NOAA Climate at a Glance, January to December average temperature, counties, Counties in Illinois by average annual temperature, 2022 [Dataset]. Available at: https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping, via Invokely: https://invokely.ai/rankings/average-annual-temperature/illinois-counties?period=2022 (Accessed: 12 October 2026).

BibTeX

@misc{noaa_counties_in_illinois_by_2022,
  author = {{NOAA National Centers for Environmental Information}},
  title = {{NOAA Climate at a Glance, January to December average temperature, counties: Counties in Illinois by average annual temperature, 2022}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/average-annual-temperature/illinois-counties?period=2022. Publisher attribution: 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.},
}

RIS

TY  - DATA
AU  - NOAA National Centers for Environmental Information
TI  - NOAA Climate at a Glance, January to December average temperature, counties: Counties in Illinois by average annual temperature, 2022
PY  - 2026
DA  - 2026/10/06
PB  - NOAA National Centers for Environmental Information
DB  - Invokely
UR  - https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping
L2  - https://invokely.ai/rankings/average-annual-temperature/illinois-counties?period=2022
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/average-annual-temperature/illinois-counties?period=2022.
N1  - Publisher attribution: 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.
ER  -

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Questions

Which county has the highest average annual temperature?

Alexander County, with 57.7 °F in 2022, according to NOAA National Centers for Environmental Information.

Which county has the lowest average annual temperature?

Jo Daviess County, with 47.1 °F in 2022.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: NOAA National Centers for Environmental Information, NOAA Climate at a Glance, January to December average temperature, counties. Retrieved 2026-10-12.