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Weather & Climate in Oconee, IL
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Oconee experiences four distinct seasons with an average annual temperature of 54°F (12°C). Winters average 28°F in January while summers reach 76°F in July. The area gets 293 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 42.3 inches. The area receives 14.5 inches of snow annually. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 668 feet.
Temperature
28°F Jan (-2°C)
76°F Jul (25°C)
| Annual Average | 53.6°F |
| 1% below US avg | |
| January Average | 28°F (-2°C) |
| July Average | 76°F (25°C) |
| Sunny Days | 293 days/yr |
Geography
| Elevation | 668 ft (204 m) |
| Area | 0.4 sq mi (0.9 km²) |
| Population Density | 514/sq mi |
| Coordinates | 39.2863°N, 89.1066°W |
| Timezone | America/Chicago |
| County | Christian County County |
| Nearest Airport | St Louis Regional (ALN) 57 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 54.0 / 100 |
| Social Vulnerability | 17.1 / 100 |
| Community Resilience | 85.0 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Low |
| Strong Wind | Relatively Moderate |
| 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
45 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M5.2.
| Apr 18, 2008 | 7 km NNE of Bellmont, Illinois | M5.2 | 141 km | 14 km |
| Apr 18, 2008 | 9 km NNE of Bellmont, Illinois | M4.7 | 141 km | 15 km |
| Apr 21, 2008 | 7 km NNE of Bellmont, Illinois | M4.0 | 142 km | 18 km |
| Nov 11, 1991 | 3 km W of Flat Rock, Illinois | M3.8 | 128 km | 0 km |
| Sep 19, 2017 | 4 km N of Bellmont, Illinois | M3.8 | 141 km | 12 km |
| Apr 25, 2008 | 8 km NNE of Bellmont, Illinois | M3.7 | 142 km | 13 km |
| Nov 20, 2012 | 7 km N of Bellmont, Illinois | M3.6 | 139 km | 19 km |
| Jun 5, 2008 | 8 km WNW of Mount Carmel, Illinois | M3.4 | 143 km | 16 km |
| May 30, 2015 | 4 km ENE of Geff, Illinois | M3.4 | 112 km | 26 km |
| Mar 2, 1990 | 9 km NW of Vernon, Illinois | M3.4 | 49 km | 0 km |
| May 1, 2008 | 8 km NNE of Bellmont, Illinois | M3.3 | 142 km | 14 km |
| May 13, 2025 | 7 km SSW of Lerna, Illinois | M3.3 | 68 km | 10 km |
| Jan 29, 1993 | 7 km WNW of Brownstown, Illinois | M3.2 | 29 km | 5 km |
| Oct 24, 1990 | 5 km ENE of Woodlawn, Illinois | M3.2 | 105 km | 1 km |
| Apr 6, 1994 | 2 km NE of Tamaroa, Illinois | M3.2 | 126 km | 15 km |
| Jul 1, 2017 | 9 km SSE of Mulberry Grove, Illinois | M3.1 | 50 km | 17 km |
| Dec 16, 1996 | 3 km NNE of Terre Haute, Indiana | M3.1 | 149 km | 5 km |
| Jul 18, 2008 | 6 km NNE of Bellmont, Illinois | M3.1 | 141 km | 18 km |
| Sep 9, 2017 | 4 km N of Bellmont, Illinois | M3.1 | 141 km | 12 km |
| Sep 5, 2004 | 3 km WNW of Saint Peter, Illinois | M2.9 | 48 km | 33 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
651 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 29 fatalities, 560 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jun 2, 1990 | EF4 | 81 km | 12.5 mi | 0 |
| Jun 2, 1990 | EF4 | 97 km | 23.0 mi | 0 |
| Mar 20, 1976 | EF4 | 63 km | 63.7 mi | 0 |
| Jun 14, 1957 | EF4 | 73 km | 4.3 mi | 2 |
| Mar 31, 2023 | EF3 | 100 km | 40.9 mi | 6 |
| Dec 1, 2018 | EF3 | 29 km | 12.5 mi | 0 |
| Nov 17, 2013 | EF3 | 91 km | 18.7 mi | 0 |
| Apr 19, 2011 | EF3 | 64 km | 4.3 mi | 0 |
| Aug 19, 2009 | EF3 | 84 km | 24.3 mi | 0 |
| Jun 1, 1999 | EF3 | 49 km | 10.0 mi | 1 |
| Apr 19, 1996 | EF3 | 60 km | 14.5 mi | 0 |
| May 9, 1995 | EF3 | 85 km | 50.0 mi | 0 |
| Dec 2, 1982 | EF3 | 100 km | 10.5 mi | 2 |
| Jul 26, 1978 | EF3 | 81 km | 8.9 mi | 0 |
| Aug 21, 1977 | EF3 | 42 km | 26.9 mi | 6 |
| Aug 6, 1977 | EF3 | 65 km | 4.1 mi | 0 |
| Jul 28, 1976 | EF3 | 70 km | 0.1 mi | 0 |
| Mar 20, 1976 | EF3 | 51 km | 8.8 mi | 0 |
| Aug 10, 1974 | EF3 | 70 km | 0.1 mi | 0 |
| Aug 10, 1974 | EF3 | 85 km | 0.1 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 28°F (-2°C) | 2.1 in | Coldest, Driest |
| February | 31°F (-1°C) | 2.1 in | |
| March | 42°F (6°C) | 3.5 in | |
| April | 53°F (12°C) | 3.9 in | |
| May | 63°F (17°C) | 4.2 in | |
| June | 72°F (22°C) | 4.3 in | Wettest |
| July | 76°F (25°C) | 3.8 in | Warmest |
| August | 74°F (24°C) | 3.1 in | |
| September | 67°F (20°C) | 3.1 in | |
| October | 56°F (13°C) | 2.9 in | |
| November | 44°F (6°C) | 3.7 in | |
| December | 32°F (0°C) | 3.1 in |
Oconee has a seasonal temperature swing of 48°F / from 28°F in January to 76°F in July. Total annual precipitation is 39.8 inches, with June being the wettest month (4.3") and January the driest (2.1").