Illinois weather in May: Statewide normals and every place, NOAA 1991-2020
In May, Illinois's statewide normal high is 74°F and normal low 52°F; normal highs run from 67°F in Waukegan to 79°F in Belleville (NOAA 1991-2020 normals).
- Statewide normal high
- 74°FMay, 1991-2020
- Statewide normal low
- 52°FMay, 1991-2020
- Statewide normal precipitation
- 4.77 inMay
- Warmest place
- 79°Fnormal high, Belleville
- Coolest place
- 67°Fnormal high, Waukegan
Where is Illinois warmest and wettest in May?
Belleville has the warmest May afternoons (79°F) and Waukegan the coolest (67°F). Anna gets the most precipitation (5.93 in) and Wheeling the least (3.76 in).
Statewide, May averaged 61.1°F in 2021, 65.3°F in 2022, 64.2°F in 2023, 67.0°F in 2024, 61.8°F in 2025, 62.5°F in 2026, against a 1991-2020 normal of 63.3°F.
| Place | High | Low | Precip. | Snow |
|---|---|---|---|---|
| Chicago | 71°F | 51°F | 4.49 | 0.0 |
| Aurora | 71°F | 50°F | 4.86 | 0.0 |
| Joliet | 71°F | 49°F | 4.53 | 0.0 |
| Rockford | 71°F | 50°F | 4.18 | 0.0 |
| Elgin | 70°F | 48°F | 5.12 | 0.0 |
| Springfield | 76°F | 54°F | 4.52 | 0.0 |
| Peoria | 74°F | 53°F | 4.69 | 0.0 |
| Champaign | 76°F | 52°F | 4.39 | – |
| Waukegan | 67°F | 47°F | – | – |
| Bloomington | 72°F | 50°F | 4.83 | – |
| Decatur | 74°F | 53°F | 4.38 | – |
| Wheaton | 74°F | 49°F | 4.46 | 0.0 |
| Normal | 74°F | 50°F | 4.81 | 0.0 |
| Moline | 74°F | 51°F | 4.67 | 0.0 |
| Crystal Lake | 71°F | 48°F | 4.98 | 0.0 |
| Romeoville | 72°F | 50°F | 4.81 | 0.0 |
| Belleville | 79°F | 56°F | 5.05 | 0.0 |
| DeKalb | 70°F | 49°F | 4.79 | 0.0 |
| Quincy | 73°F | 54°F | 4.55 | – |
| Streamwood | 73°F | 47°F | 4.66 | 0.0 |
| Wheeling | 70°F | 50°F | 3.76 | – |
| Rock Island | 72°F | 51°F | 5.12 | – |
| Mundelein | 68°F | 47°F | 4.57 | 0.0 |
| Galesburg | 72°F | 52°F | 5.27 | 0.0 |
| Burbank | 72°F | 52°F | 4.75 | 0.0 |
| Danville | 75°F | 52°F | 4.63 | – |
| West Chicago | 71°F | 49°F | 4.34 | – |
| Alton | 75°F | 56°F | 5.46 | – |
| Lisle | 71°F | 47°F | 4.79 | – |
| Kankakee | 73°F | 51°F | 5.15 | 0.0 |
| Freeport | 70°F | 48°F | 4.36 | 0.0 |
| Carbondale | 77°F | 55°F | 4.98 | – |
| Park Forest | 71°F | 49°F | 4.57 | 0.0 |
| Ottawa | 72°F | 51°F | 4.48 | 0.0 |
| Jacksonville | 75°F | 53°F | 5.09 | – |
| Charleston | 77°F | 54°F | 4.52 | 0.0 |
| Cahokia Heights | 77°F | 57°F | 4.84 | – |
| Mattoon | 74°F | 54°F | 3.86 | – |
| Dixon | 71°F | 51°F | 4.82 | 0.0 |
| Antioch | 68°F | 48°F | – | – |
| Morris | 72°F | 51°F | 4.39 | 0.0 |
| Channahon | 72°F | 51°F | 4.61 | 0.0 |
| Mount Vernon | 74°F | 55°F | 5.06 | 0.0 |
| Lincoln | 75°F | 52°F | 4.37 | 0.0 |
| Effingham | 76°F | 54°F | 5.27 | 0.0 |
| Streator | 74°F | 52°F | 4.69 | 0.0 |
| Rantoul | 75°F | 51°F | 4.33 | – |
| Kewanee | 72°F | 50°F | 5.07 | 0.0 |
| Pontiac | 74°F | 52°F | 4.43 | 0.0 |
| Barrington | 69°F | 48°F | 5.15 | 0.0 |
| Peru | 73°F | 49°F | 4.49 | 0.0 |
| Rochelle | 70°F | 48°F | 4.69 | – |
| Lake Villa | 69°F | 48°F | 4.44 | 0.0 |
| Monmouth | 73°F | 51°F | 5.18 | 0.0 |
| Olney | 75°F | 53°F | 5.60 | 0.0 |
| Jerseyville | 74°F | 54°F | 5.29 | 0.0 |
| Paris | 73°F | 51°F | 4.17 | 0.0 |
| Harrisburg | 78°F | 57°F | 4.31 | – |
| Marengo | 70°F | 47°F | 4.57 | 0.0 |
| Princeton | 73°F | 50°F | 5.07 | 0.0 |
| Vandalia | 75°F | 54°F | 5.30 | – |
| Robinson | 76°F | 54°F | 4.67 | – |
| Salem | 76°F | 55°F | 4.99 | 0.0 |
| Mount Carmel | 76°F | 57°F | 5.83 | 0.0 |
| Benton | 76°F | 56°F | – | – |
| Geneseo | 74°F | 52°F | 4.87 | 0.0 |
| Hillsboro | 78°F | 54°F | 5.06 | – |
| Du Quoin | 76°F | 56°F | 5.51 | 0.0 |
| Carlinville | 74°F | 54°F | 4.27 | 0.0 |
| Pana | 76°F | 52°F | 4.75 | 0.0 |
| Fairfield | 78°F | 56°F | 4.98 | – |
| Marseilles | 73°F | 49°F | 4.70 | 0.0 |
| Hoopeston | 74°F | 53°F | 4.78 | 0.0 |
| Carmi | 77°F | 54°F | 5.16 | 0.0 |
| Tuscola | 74°F | 53°F | 4.24 | 0.0 |
| Flora | 77°F | 54°F | 5.09 | 0.0 |
| Shelbyville | 74°F | 54°F | 4.65 | – |
| Watseka | 74°F | 50°F | 4.41 | 0.0 |
| Paxton | 73°F | 51°F | 4.51 | 0.0 |
| Lawrenceville | 77°F | 56°F | 4.85 | – |
| Sullivan | 75°F | 53°F | 4.98 | 0.0 |
| Anna | 79°F | 56°F | 5.93 | 0.0 |
| Pittsfield | 75°F | 54°F | 4.83 | 0.0 |
| Sparta | 76°F | 54°F | 5.17 | 0.0 |
| Dwight | 72°F | 49°F | 4.85 | 0.0 |
| Morrison | 71°F | 49°F | 4.73 | 0.0 |
| Fulton | 71°F | 51°F | 4.03 | – |
| Aledo | 73°F | 50°F | 5.06 | 0.0 |
| Gibson City | 73°F | 51°F | 4.51 | 0.0 |
| Carlyle | 76°F | 56°F | 5.23 | – |
| Galena | 69°F | 47°F | 4.38 | 0.3 |
| Virden | 76°F | 55°F | 4.19 | 0.0 |
| Nashville | 75°F | 56°F | 4.81 | 0.0 |
| Rushville | 72°F | 52°F | 5.33 | – |
| Knoxville | 72°F | 51°F | 5.54 | 0.0 |
| Havana | 75°F | 53°F | 5.08 | 0.0 |
| Newton | 75°F | 55°F | 4.79 | 0.0 |
| McLeansboro | 77°F | 55°F | 4.94 | 0.0 |
| Galva | 73°F | 50°F | 4.82 | – |
| Casey | 76°F | 54°F | 4.48 | 0.0 |
| Polo | 73°F | 49°F | 4.72 | – |
| White Hall | 74°F | 53°F | 4.81 | 0.0 |
| Petersburg | 74°F | 53°F | 4.61 | 0.0 |
| Mason City | 74°F | 53°F | 4.47 | 0.0 |
| Athens | 74°F | 51°F | 4.52 | – |
| Minonk | 74°F | 51°F | 4.60 | 0.0 |
| Albion | 77°F | 57°F | – | – |
| Lacon | 75°F | 52°F | 4.76 | 0.0 |
| Princeville | 75°F | 51°F | 5.05 | 0.0 |
| Chenoa | 73°F | 51°F | 4.52 | 0.0 |
| Stockton | 71°F | 49°F | 4.13 | 0.1 |
| Cairo | 78°F | 58°F | 5.08 | – |
| Winchester | 75°F | 52°F | 4.81 | – |
| Grayville | 78°F | 55°F | 5.75 | 0.0 |
| Mount Carroll | 72°F | 47°F | 4.57 | 0.0 |
| Neoga | 75°F | 54°F | 4.68 | – |
| Walnut | 72°F | 51°F | 4.63 | 0.0 |
| Palestine | 76°F | 55°F | 4.91 | 0.0 |
| La Harpe | 72°F | 52°F | 5.22 | – |
| Windsor | 74°F | 53°F | 4.57 | 0.0 |
| Morrisonville | 75°F | 54°F | 4.55 | 0.0 |
| Rosiclare | 75°F | 53°F | 5.35 | 0.0 |
| Ramsey | 73°F | 53°F | 4.75 | 0.0 |
| Shabbona | 70°F | 48°F | 4.59 | – |
| Paw Paw | 70°F | 48°F | 4.83 | 0.0 |
| Hennepin | 74°F | 51°F | 4.76 | – |
| Piper City | 76°F | 49°F | 4.91 | 0.0 |
| Ogden | 73°F | 52°F | 4.96 | 0.0 |
| Brookport | 77°F | 56°F | 4.83 | 0.0 |
| Elizabeth | 70°F | 47°F | 4.29 | 0.0 |
| Brownstown | 75°F | 55°F | 5.34 | – |
| Avon | 72°F | 49°F | 4.95 | 0.0 |
| Golden | 74°F | 52°F | – | – |
| New Boston | 73°F | 52°F | 5.05 | – |
| Congerville | 74°F | 52°F | 4.77 | 0.0 |
| Sidell | 73°F | 53°F | 4.66 | 0.0 |
| Altona | 72°F | 49°F | 5.21 | – |
| Prairie City | 74°F | 52°F | 5.05 | 0.0 |
| Perry | 75°F | 53°F | 4.41 | 0.0 |
| Compton | 71°F | 49°F | – | – |
| Gladstone | 73°F | 53°F | 5.02 | 0.0 |
| Bentley | 74°F | 53°F | 5.28 | 0.0 |
| Kaskaskia | 77°F | 55°F | 5.18 | 0.0 |
| Illinois City | 72°F | 51°F | 4.82 | – |
| Cahokia | 76°F | 56°F | 4.80 | 0.0 |
| Chicago Aurora Municipal Airport | 72°F | 49°F | 4.06 | – |
| Chicago Botanic Garden | 68°F | 48°F | 4.84 | 0.0 |
| Chicago Midway Airport | 71°F | 52°F | 4.09 | – |
| Chicago Waukegan Regional Airport | 67°F | 46°F | 3.92 | – |
| Dixon Springs Agricultural Center | 77°F | 56°F | 5.19 | 0.0 |
| Grand Chain Dam 53 | 77°F | 56°F | 4.92 | 0.0 |
| Iuka (12 mi SW) | 75°F | 54°F | 5.20 | 0.0 |
| Little Red School House | 73°F | 50°F | 4.98 | – |
| McHenry W.G. Stratton Lock and Dam | 70°F | 47°F | 4.47 | 0.0 |
| Rend Lake Dam | 76°F | 56°F | 5.07 | – |
| Smithland Lock and Dam | 77°F | 56°F | 4.56 | 0.0 |
Source: NOAA NCEI nClimDiv statewide normals; NOAA NCEI 1991-2020 monthly normals for each station.