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Weather & Climate in Shannon, IL
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Shannon experiences four distinct seasons with an average annual temperature of 49°F (10°C). Winters average 22°F in January while summers reach 73°F in July. The area gets 246 sunny days per year, above the national average. Annual precipitation totals 40.0 inches. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 929 feet.
Temperature
22°F Jan (-6°C)
73°F Jul (23°C)
| Annual Average | 49.3°F |
| 9% below US avg | |
| January Average | 22°F (-6°C) |
| July Average | 73°F (23°C) |
| Sunny Days | 246 days/yr |
Geography
| Elevation | 929 ft (283 m) |
| Area | 0.2 sq mi (0.5 km²) |
| Population Density | 1,608/sq mi |
| Coordinates | 42.1524°N, 89.7402°W |
| Timezone | America/Chicago |
| County | Carroll County County |
| Nearest Airport | Chicago/Rockford International (RFD) 33 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 39.0 / 100 |
| Social Vulnerability | 55.4 / 100 |
| Community Resilience | 69.4 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Moderate |
| Strong Wind | Relatively Moderate |
| Heat Wave | Very Low |
| Winter Weather | Relatively Low |
| Lightning | Very Low |
| Ice Storm | Relatively Low |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Low |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
6 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 | 104 km | 10 km |
| Feb 10, 2010 | 2 km NW of Lily Lake, Illinois | M3.8 | 105 km | 10 km |
| Sep 2, 1999 | 8 km W of Amboy, Illinois | M3.5 | 54 km | 5 km |
| Jul 15, 2024 | 2 km WNW of Somonauk, Illinois | M3.1 | 102 km | 10 km |
| Mar 25, 2015 | 3 km WNW of Lake in the Hills, Illinois | M2.9 | 113 km | 6 km |
| Jun 10, 2013 | 4 km NNE of Virgil, Illinois | M2.6 | 103 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
568 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 41 fatalities, 924 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jun 7, 1984 | EF5 | 93 km | 36.0 mi | 9 |
| Apr 9, 2015 | EF4 | 50 km | 30.1 mi | 2 |
| Jul 3, 1983 | EF4 | 96 km | 0.5 mi | 0 |
| Mar 29, 1981 | EF4 | 55 km | 5.1 mi | 0 |
| Apr 21, 1967 | EF4 | 68 km | 25.5 mi | 24 |
| Jun 16, 2014 | EF3 | 96 km | 1.0 mi | 0 |
| Jan 7, 2008 | EF3 | 79 km | 13.2 mi | 0 |
| Aug 18, 2005 | EF3 | 89 km | 18.6 mi | 1 |
| May 9, 1995 | EF3 | 95 km | 22.0 mi | 0 |
| Jun 19, 1993 | EF3 | 83 km | 14.0 mi | 0 |
| Jun 17, 1992 | EF3 | 83 km | 16.0 mi | 0 |
| Mar 13, 1990 | EF3 | 76 km | 15.5 mi | 0 |
| May 8, 1988 | EF3 | 97 km | 32.0 mi | 0 |
| May 8, 1988 | EF3 | 62 km | 16.0 mi | 0 |
| Aug 5, 1979 | EF3 | 20 km | 5.7 mi | 0 |
| Jun 30, 1977 | EF3 | 88 km | 6.1 mi | 0 |
| Jun 20, 1974 | EF3 | 48 km | 10.6 mi | 1 |
| May 13, 1974 | EF3 | 93 km | 3.6 mi | 0 |
| Sep 9, 1970 | EF3 | 86 km | 4.7 mi | 0 |
| Apr 16, 1967 | EF3 | 44 km | 27.8 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
1 wildfire (100+ acres) recorded within 100 km. Largest: COLD SPRINGS (552 acres, 2009).
| Year | Name | Acres Burned | Distance |
| 2009 | COLD SPRINGS | 552 | 59 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 22°F (-6°C) | 1.3 in | Coldest, Driest |
| February | 23°F (-5°C) | 1.3 in | |
| March | 35°F (2°C) | 2.5 in | |
| April | 47°F (9°C) | 3.5 in | |
| May | 59°F (15°C) | 4.3 in | |
| June | 68°F (20°C) | 4.5 in | Wettest |
| July | 73°F (23°C) | 3.6 in | Warmest |
| August | 70°F (21°C) | 4.3 in | |
| September | 62°F (17°C) | 3.7 in | |
| October | 50°F (10°C) | 2.8 in | |
| November | 36°F (2°C) | 2.7 in | |
| December | 24°F (-5°C) | 2.0 in |
Shannon has a seasonal temperature swing of 51°F / from 22°F in January to 73°F in July. Total annual precipitation is 36.7 inches, with June being the wettest month (4.5") and January the driest (1.3").