PlainClimate

NOAA climate atlas · updated August 2026

Illinois Climate Data

Climate normals for 163 station-mapped locations, each from its primary station in Illinois's 453-station NOAA network.

average temperature
52°F (11°C)52.2°F · fleet p50 52.2°F · n=50
At national median
annual precipitation
40.7"40.7 inches · fleet p50 43.7 inches · n=50
Drier than median
annual snowfall
21.3"21.3 inches · fleet p50 24.7 inches · n=50
Less snow than median
locations / stations
163 / 453State coverage: 163 locations / 453 stations. Benchmark context: this profile's measured location and NOAA-station counts.
State coverage

Illinois's climate in one line

Illinois averages 52°F a year - cooler than 52% of U.S. states, spanning Galena at 47°F to Anna at 59°F.

52°F
statewide average · 48th percentile of states
41"
average annual precipitation
83/100
most comfortable: Brookport Dam
163
station-mapped locations · 453 NOAA stations

Statewide figures are simple averages across 163 station-mapped locations (each from its primary NOAA station), local conditions vary widely by elevation and coast distance.

How Illinois ranks among all 50 states

Illinois's average temperature vs. all U.S. states

Statewide annual mean temperature, NOAA 1991–2020 normals

52°F 48th percentile cooler than 52% of 50 U.S. states

30°F–35°F: 1 US states (2%). Below this entry. 35°F–40°F: 0 US states (0%). Below this entry. 40°F–45°F: 8 US states (16%). Below this entry. 45°F–50°F: 10 US states (20%). Below this entry. 50°F–55°F: 12 US states (24%). This entry sits in this band. 55°F–60°F: 8 US states (16%). Above this entry. 60°F–65°F: 7 US states (14%). Above this entry. 65°F–70°F: 2 US states (4%). Above this entry. 70°F–75°F: 2 US states (4%). Above this entry. This state 30°F 75°F every U.S. state, bucketed by value
  1. 30°F–35°F: 1 US states (2%). Below this entry.
  2. 35°F–40°F: 0 US states (0%). Below this entry.
  3. 40°F–45°F: 8 US states (16%). Below this entry.
  4. 45°F–50°F: 10 US states (20%). Below this entry.
  5. 50°F–55°F: 12 US states (24%). This entry sits in this band.
  6. 55°F–60°F: 8 US states (16%). Above this entry.
  7. 60°F–65°F: 7 US states (14%). Above this entry.
  8. 65°F–70°F: 2 US states (4%). Above this entry.
  9. 70°F–75°F: 2 US states (4%). Above this entry.

Source NOAA U.S. Climate Normals (statewide aggregate) · 1991–2020

Each bar is a band; taller bars hold more US states. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.

Illinois in the national rankings

Temperature × precipitation · 50-state landscape

Illinois in the national climate landscape

Illinois averages 52.2°F and 40.7 inches of annual precipitation across 163 station-mapped locations. Against the same complete 50-state cohort, that places it in the cooler and drier half of the chart. Dashed lines mark the national medians of 52.3°F and 43.7 inches.

IL · Illinois52.2°F · 40.7 in · cooler and drier than the medians
Cooler + wetterWarmer + wetterCooler + drierWarmer + drier31.5°F42.3°F53.0°F63.8°F74.6°F6.3"20.5"34.6"48.7"62.9"Annual mean temperatureAnnual precipitationAK · 172 locations: 33.5°F, 47.6"AL · 100 locations: 63.3°F, 57.9"AR · 110 locations: 60.7°F, 52.2"AZ · 169 locations: 62.3°F, 12.4"CA · 363 locations: 59.8°F, 21.6"CO · 214 locations: 46.3°F, 15.9"CT · 23 locations: 50.1°F, 48.6"DE · 7 locations: 56.2°F, 46.8"FL · 165 locations: 72.6°F, 55.2"GA · 122 locations: 63.4°F, 52"HI · 49 locations: 72.4°F, 48.5"IA · 143 locations: 48°F, 35.9"ID · 139 locations: 46.1°F, 18"IL · 163 locations: 52.2°F, 40.7"IL · 163 locationsIN · 116 locations: 52.4°F, 43.7"KS · 168 locations: 54.8°F, 31.2"KY · 95 locations: 56.2°F, 50.6"LA · 91 locations: 67.3°F, 60.3"MA · 68 locations: 49.2°F, 48.2"MD · 42 locations: 55.6°F, 45.5"ME · 79 locations: 43.1°F, 46.4"MI · 201 locations: 45.5°F, 34.2"MN · 172 locations: 42.2°F, 30"MO · 164 locations: 55.1°F, 43.9"MS · 91 locations: 64.1°F, 59.7"MT · 215 locations: 43.4°F, 15.9"NC · 178 locations: 59.1°F, 52.2"ND · 119 locations: 41°F, 19.2"NE · 171 locations: 49.6°F, 25"NH · 52 locations: 44.5°F, 46.6"NJ · 45 locations: 53.6°F, 47.9"NM · 167 locations: 54.3°F, 13.8"NV · 115 locations: 52.4°F, 8.9"NY · 173 locations: 47.5°F, 43.7"OH · 128 locations: 51.6°F, 41.1"OK · 159 locations: 60.3°F, 35.7"OR · 180 locations: 50.5°F, 37.6"PA · 157 locations: 50.2°F, 45.2"RI · 9 locations: 51.2°F, 48.7"SC · 100 locations: 62.8°F, 49.8"SD · 149 locations: 45.6°F, 21.8"TN · 146 locations: 58°F, 56"TX · 449 locations: 66.2°F, 31.1"UT · 170 locations: 49.4°F, 13.9"VA · 119 locations: 55.8°F, 46"VT · 41 locations: 43.5°F, 43.7"WA · 149 locations: 49.9°F, 40.9"WI · 200 locations: 44.5°F, 34.6"WV · 99 locations: 52.3°F, 47.6"WY · 144 locations: 43.3°F, 14"
Read all 50 state values

Each point is PlainClimate's simple average across the station-mapped location normals available for that state. Cohort sizes vary and are shown below; the values are not population weighted. Dashed lines mark the median of this 50-state comparison and are guides, not comfort or safety thresholds.

StateLocationsAnnual meanAnnual precipitation
Alaska17233.5°F47.6 in
Alabama10063.3°F57.9 in
Arkansas11060.7°F52.2 in
Arizona16962.3°F12.4 in
California36359.8°F21.6 in
Colorado21446.3°F15.9 in
Connecticut2350.1°F48.6 in
Delaware756.2°F46.8 in
Florida16572.6°F55.2 in
Georgia12263.4°F52.0 in
Hawaii4972.4°F48.5 in
Iowa14348.0°F35.9 in
Idaho13946.1°F18.0 in
Illinois16352.2°F40.7 in
Indiana11652.4°F43.7 in
Kansas16854.8°F31.2 in
Kentucky9556.2°F50.6 in
Louisiana9167.3°F60.3 in
Massachusetts6849.2°F48.2 in
Maryland4255.6°F45.5 in
Maine7943.1°F46.4 in
Michigan20145.5°F34.2 in
Minnesota17242.2°F30.0 in
Missouri16455.1°F43.9 in
Mississippi9164.1°F59.7 in
Montana21543.4°F15.9 in
North Carolina17859.1°F52.2 in
North Dakota11941.0°F19.2 in
Nebraska17149.6°F25.0 in
New Hampshire5244.5°F46.6 in
New Jersey4553.6°F47.9 in
New Mexico16754.3°F13.8 in
Nevada11552.4°F8.9 in
New York17347.5°F43.7 in
Ohio12851.6°F41.1 in
Oklahoma15960.3°F35.7 in
Oregon18050.5°F37.6 in
Pennsylvania15750.2°F45.2 in
Rhode Island951.2°F48.7 in
South Carolina10062.8°F49.8 in
South Dakota14945.6°F21.8 in
Tennessee14658.0°F56.0 in
Texas44966.2°F31.1 in
Utah17049.4°F13.9 in
Virginia11955.8°F46.0 in
Vermont4143.5°F43.7 in
Washington14949.9°F40.9 in
Wisconsin20044.5°F34.6 in
West Virginia9952.3°F47.6 in
Wyoming14443.3°F14.0 in

Derived by PlainClimate from NOAA 1991-2020 U.S. Climate Normals · simple averages across each state's varying station-mapped-location cohort · data updated August 2026.

Illinois Climate in Context

U.S. land-mean temperature anomaly (NOAA NCEI) tracked against global anomaly (NASA GISTEMP). Paris Agreement 1.5°C and 2.0°C thresholds shown as reference lines. Illinois sits within this national warming envelope; individual station-mapped locations below show local readings against this trend.

Illinois within U.S. vs Global Warming, 1900-2024 Anomaly chart from 1900 to 2024. Local series shows warming of 0.11 °C per decade versus a global rate of 0.11 °C per decade (ratio 1.00). Paris Agreement thresholds at 1.5 and 2.0 °C are dashed. -1.0°C -0.5°C +0.0°C +0.5°C +1.0°C +1.5°C +2.0°C +2.5°C Paris 1.5°C Paris 2.0°C 1900192019401960198020002020
  • United States (incl. Illinois) +0.11 °C/decade
  • Global (NASA GISTEMP) +0.11 °C/decade
  • Paris Agreement thresholds 1.5°C / 2.0°C
Sources: NOAA NCEI U.S. Climate Normals + NASA GISTEMP land-ocean.

Station-mapped locations in Illinois

163 locations with climate data

Scroll the table to browse every location, or use the complete CSV and JSON exports below.

Location Avg Temp Precip
Albion 57°F N/A
Aledo 50°F 39.1"
Alton - Melvin Price L&d 56°F 41.9"
Altona 49°F 39.4"
Anna 59°F 51.1"
Antioch 49°F N/A
Athens 52°F 38.4"
Aurora 50°F 39.5"
Avon 49°F 37.6"
Barrington 48°F 40.4"
Belleville Siu Rsch 58°F 43.4"
Bentley 53°F 40.1"
Benton 56°F N/A
Bloomington 50°F 40.4"
Brookport Dam 57°F 49.1"
Brownstown 55°F 41.2"
Cahokia 56°F 42.8"
Cahokia St Louis 57°F 40.8"
Cairo 58°F 51.0"
Carbondale Sewage Plt 56°F 49.0"
Carbondale Southern IL 56°F 44.0"
Carlinville 53°F 40.0"
Carlyle Rsvr 56°F 45.9"
Carmi 55°F 48.3"
Casey 54°F 45.5"
Champaign 51°F 39.6"
Champaign Willard 53°F 37.0"
Channahon Dresden Isl Dam 51°F 37.2"
Charleston 55°F 43.8"
Chenoa 51°F 36.3"
Chicago 51°F 37.9"
Chicago Aurora Muni 49°F 33.8"
Chicago Botanic Garden 50°F 39.5"
Chicago Midway 52°F 34.4"
Chicago Northerly Island 51°F N/A
Chicago Palwaukee 51°F 32.3"
Chicago Waukegan Rgnl 48°F 35.3"
Compton 48°F N/A
Congerville 52°F 37.5"
Crystal Lake 49°F 39.4"
Danville 53°F 43.2"
De Kalb 49°F 37.3"
Decatur 53°F 36.4"
Decatur Wtp 53°F 40.4"
Dixon 49°F 40.5"
Dixon Springs Agric Ctr 57°F 50.5"
Du Quoin 56°F 47.7"
Dwight 49°F 37.7"
Effingham 54°F 44.0"
Elgin 49°F 39.9"
Elizabeth 48°F 39.4"
Fairfield Radio Wfiw 57°F 46.0"
Flora 55°F 48.0"
Freeport Waste Wtp 48°F 38.4"
Fulton L&d 50°F 34.3"
Galena 47°F 39.6"
Galesburg 50°F 39.0"
Galva 50°F 38.7"
Geneseo 51°F 39.1"
Gibson City 51°F 37.7"
Gladstone Dam 52°F 37.2"
Golden 52°F N/A
Grand Chain Dam 58°F 49.4"
Grayville 56°F 50.0"
Harrisburg 57°F 47.6"
Havana 53°F 41.0"
Hennepin 51°F 38.6"
Hennepin Wtr Trmt Plt 51°F N/A
Hillsboro 56°F 42.1"
Hoopeston 52°F 40.9"
Illinois City Dam 50°F 36.4"
Iuka 55°F 44.7"
Jacksonville 53°F 39.3"
Jerseyville 53°F 42.2"
Joliet Brandon RD Dam 50°F 38.0"
Kankakee Metro Wastewater 51°F 41.7"
Kaskaskia Rvr Navigation Lock 56°F 42.8"
Kewanee 50°F 39.6"
Knoxville 50°F 40.5"
La Harpe 51°F 39.1"
Lacon 53°F 38.4"
Lake Villa 49°F 37.8"
Lawrenceville 56°F 41.7"
Lincoln 52°F 39.8"
Lisle-morton Arboretum 49°F 40.2"
Little Red School Hse 51°F 41.4"
Marengo 48°F 37.6"
Marseilles Lock 50°F 39.0"
Mason City 52°F 39.3"
Mattoon 54°F 41.3"
Mattoon Coles County 53°F 36.0"
McHenry -wg Stratton L&d 49°F 37.0"
Mcleansboro 55°F 47.1"
Minonk 51°F 37.6"
Moline Quad City 51°F 38.3"
Monmouth 51°F 39.4"
Morris 51°F 38.8"
Morrison 48°F 38.3"
Morrisonville 54°F 38.1"
Mt Carmel 56°F 48.7"
Mt Carroll 49°F 40.3"
Mt Vernon 55°F 45.0"
Mundelein 48°F 38.5"
Nashville 55°F 42.2"
Neoga 54°F 41.9"
New Boston Dam 51°F 36.3"
Newton 55°F 46.0"
Normal 51°F 39.4"
Ogden 52°F 41.2"
Olney 54°F 48.8"
Ottawa 50°F 36.2"
Palestine 55°F 46.3"
Pana 54°F 42.3"
Paris Stp 51°F 42.7"
Park Forest 50°F 42.1"
Paw Paw 48°F 36.8"
Paxton 51°F 37.9"
Peoria Gtr Peoria 53°F 37.5"
Perry 53°F 39.1"
Peru 50°F 38.0"
Petersburg 52°F 37.6"
Piper City 52°F 44.4"
Pittsfield 54°F 40.5"
Polo 49°F 40.0"
Pontiac 52°F 37.0"
Prairie City 52°F 38.5"
Princeton 50°F 39.8"
Princeville 51°F 38.8"
Quincy 53°F 36.4"
Quincy Dam 54°F 36.5"
Ramsey 53°F 42.5"
Rantoul 52°F 40.4"
Rend Lake Dam 56°F 46.0"
Robinson 54°F 45.5"
Rochelle 48°F 36.6"
Rock Island L&d 50°F 38.8"
Rockford Gtr Rockford 49°F 37.2"
Romeoville 51°F 41.1"
Rosiclare 55°F 50.9"
Rushville 52°F 40.9"
Salem 55°F 45.9"
Shabbona 48°F 37.4"
Shelbyville Dam 54°F 41.4"
Sidell 52°F 40.4"
Smithland L&d 57°F 49.3"
Sparta 55°F 45.6"
Springfield 53°F 40.5"
Springfield Capital 54°F 38.0"
Stockton 48°F 38.7"
Streamwood 50°F 38.0"
Streator 52°F 39.4"
Sullivan 53°F 41.6"
Tuscola 52°F 40.5"
Vandalia 54°F 43.7"
Virden 55°F 38.4"
Walnut 49°F 36.8"
Watseka 51°F 38.4"
Waukegan 48°F N/A
West Chicago Dupage 50°F 33.2"
Wheaton 51°F 39.9"
White Hall 53°F 39.6"
Winchester 53°F 40.4"
Windsor 53°F 41.2"

Source: NOAA National Centers for Environmental Information U.S. Climate Normals v1.0.1 · 1991-2020 Statewide aggregates for Illinois computed as the simple average across its 163 station-mapped locations, each represented by its primary NOAA station (453 stations in the state network).

Climate Insight: Illinois

Illinois's climate profile is aggregated from 163 station-mapped locations and 453 NOAA weather stations reporting under the 1991–2020 U.S. Climate Normals program. The statewide average annual temperature sits at 52°F, which is the simple average across all tracked station-mapped locations rather than any single station's reading. Because Illinois spans multiple latitudes, elevations, and proximities to large water bodies, local conditions can differ from this headline number by wide margins; coastal, valley, and mountain stations often diverge by ten degrees or more even within a single month.

Precipitation and snowfall averages round out the climatological picture. Across Illinois, annual precipitation averages 40.7 inches, with typical seasonal snowfall near 21.3 inches statewide. These numbers combine rain, sleet, and snow water-equivalent and describe the thirty-year normal rather than any particular recent year. Readers evaluating a specific destination should drill into one of the 163 individual location profiles below; each station record varies with local geography, and the statewide figures here are averages that mask meaningful intrastate differences.

For planning purposes, the location table above is sorted to help you compare averages side-by-side: annual mean temperature, average daily high and low, precipitation totals, snowfall, and PlainClimate's climate comfort score. That 1–100 score combines temperature mildness, precipitation moderation, snowfall burden, and frost-free growing-season length from each location's NOAA normal. It is a climate-only comparison, not a NOAA or overall livability rating. Use it as a starting point, then open each location profile for the exact score inputs, monthly breakdowns, degree-day totals, frost dates, and separately reported humidity metrics.

Nationwide similar states

Other states closest to Illinois on two NOAA statewide-average axes (annual temperature and annual precipitation). Chip rows use distinct link sets.

Closest by average temperature

Nearest 50-state peers by avg_temp (52°F here).

Closest by annual precipitation

Nearest peers by avg_precip (40.7" here), excluding temperature-peer codes.

National state rankings →

Frequently Asked Questions

What is the average temperature in Illinois?
Illinois averages 52°F a year across NOAA's 1991-2020 Climate Normals, cooler than 52% of U.S. states. That is 0.9°F below the 53.1°F average across all 50 states.
Does the climate vary a lot within Illinois?
Yes. Annual averages inside Illinois run from Galena at 47°F to Anna at 59°F -- a 12°F spread between the state's coldest and warmest measured station-mapped locations. A single statewide average can mask this kind of local variation.
Where does Illinois rank nationally for temperature?
Illinois ranks #26 warmest and #25 coldest out of 50 U.S. states and territories with NOAA normals data, based on statewide average annual temperature.
What is the most comfortable station-mapped location in Illinois?
Brookport Dam scores the highest established comfort rating in Illinois at 83/100, a PlainClimate composite of annual temperature mildness, precipitation moderation, snowfall burden, and frost-free growing-season length.

Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). For informational purposes only.

Every figure on PlainClimate is rendered directly from NOAA 1991-2020 U.S. Climate Normals data, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.