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Weather & Climate in McLean, IL
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
McLean experiences four distinct seasons with an average annual temperature of 50°F (10°C). Winters average 23°F in January while summers reach 74°F in July. The area gets 275 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 40.4 inches. Air quality is rated Good with a median AQI of 44. 69% of days have good air quality. The city sits at an elevation of 708 feet.
Temperature
23°F Jan (-5°C)
74°F Jul (23°C)
| Annual Average | 50.2°F |
| 7% below US avg | |
| January Average | 23°F (-5°C) |
| July Average | 74°F (23°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 708 ft (216 m) |
| Area | 0.2 sq mi (0.4 km²) |
| Population Density | 619/sq mi |
| Coordinates | 40.3136°N, 89.1686°W |
| Timezone | America/Chicago |
| County | Logan County County |
| Nearest Airport | Central Il Regional/Bloomington-Normal (BMI) 17 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 44.0 |
| Rating | Good |
| Good Days % | 69.4% |
| Unhealthy Days | 1 |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 58.1 / 100 |
| Social Vulnerability | 38.4 / 100 |
| Community Resilience | 82.2 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | Very Low |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Low |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Relatively Low |
| Drought | Relatively High |
| Cold Wave | Relatively Moderate |
| Landslide | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
4 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.2.
| Jun 28, 2004 | 12 km NW of Dayton, Illinois | M4.2 | 130 km | 10 km |
| May 13, 2025 | 7 km SSW of Lerna, Illinois | M3.3 | 128 km | 10 km |
| Jan 29, 1993 | 7 km WNW of Brownstown, Illinois | M3.2 | 143 km | 5 km |
| Mar 15, 2025 | 6 km W of Dwight, Illinois | M2.6 | 103 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
815 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 22 fatalities, 879 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Nov 17, 2013 | EF4 | 48 km | 46.4 mi | 3 |
| Jul 13, 2004 | EF4 | 56 km | 9.6 mi | 0 |
| May 13, 1995 | EF4 | 96 km | 7.0 mi | 0 |
| May 5, 1977 | EF4 | 10 km | 7.3 mi | 0 |
| Jun 29, 1976 | EF4 | 73 km | 4.9 mi | 0 |
| Mar 20, 1976 | EF4 | 65 km | 63.7 mi | 0 |
| Jun 14, 1957 | EF4 | 77 km | 4.3 mi | 2 |
| Apr 4, 2023 | EF3 | 98 km | 19.9 mi | 0 |
| Feb 28, 2017 | EF3 | 69 km | 17.8 mi | 0 |
| Nov 17, 2013 | EF3 | 89 km | 18.7 mi | 0 |
| Nov 17, 2013 | EF3 | 86 km | 29.8 mi | 0 |
| Dec 31, 2010 | EF3 | 69 km | 3.6 mi | 0 |
| Jun 5, 2010 | EF3 | 95 km | 8.6 mi | 0 |
| Aug 19, 2009 | EF3 | 52 km | 24.3 mi | 0 |
| May 10, 2003 | EF3 | 47 km | 17.5 mi | 0 |
| Apr 19, 1996 | EF3 | 83 km | 4.0 mi | 0 |
| Apr 19, 1996 | EF3 | 55 km | 14.5 mi | 0 |
| Apr 19, 1996 | EF3 | 15 km | 9.4 mi | 0 |
| May 13, 1995 | EF3 | 66 km | 25.0 mi | 0 |
| May 9, 1995 | EF3 | 68 km | 50.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 23°F (-5°C) | 1.7 in | Coldest |
| February | 29°F (-2°C) | 1.6 in | Driest |
| March | 40°F (5°C) | 3.2 in | |
| April | 52°F (11°C) | 3.7 in | |
| May | 63°F (17°C) | 4.4 in | Wettest |
| June | 72°F (22°C) | 4.0 in | |
| July | 74°F (23°C) | 4.1 in | Warmest |
| August | 73°F (23°C) | 3.7 in | |
| September | 66°F (19°C) | 3.5 in | |
| October | 54°F (12°C) | 2.8 in | |
| November | 41°F (5°C) | 2.9 in | |
| December | 29°F (-1°C) | 2.7 in |
McLean has a seasonal temperature swing of 51°F / from 23°F in January to 74°F in July. Total annual precipitation is 38.1 inches, with May being the wettest month (4.4") and February the driest (1.6").