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Weather & Climate in Nilwood, IL
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Nilwood experiences four distinct seasons with an average annual temperature of 53°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 40.0 inches. The area receives 16.5 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 670 feet.
Temperature
28°F Jan (-2°C)
76°F Jul (25°C)
| Annual Average | 53.4°F |
| 1% below US avg | |
| January Average | 28°F (-2°C) |
| July Average | 76°F (25°C) |
| Sunny Days | 293 days/yr |
Geography
| Elevation | 670 ft (204 m) |
| Area | 0.2 sq mi (0.5 km²) |
| Population Density | 298/sq mi |
| Coordinates | 39.3995°N, 89.8077°W |
| Timezone | America/Chicago |
| County | Macoupin County County |
| Nearest Airport | St Louis Regional (ALN) 37 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 79.9 / 100 |
| Social Vulnerability | 50.7 / 100 |
| Community Resilience | 72.7 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | Very Low |
| Earthquake | Relatively Moderate |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Moderate |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively Moderate |
| Lightning | Relatively High |
| Ice Storm | Relatively Low |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Moderate |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
17 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.4.
| Mar 2, 1990 | 9 km NW of Vernon, Illinois | M3.4 | 82 km | 0 km |
| May 13, 2025 | 7 km SSW of Lerna, Illinois | M3.3 | 127 km | 10 km |
| Oct 24, 1990 | 5 km ENE of Woodlawn, Illinois | M3.2 | 138 km | 1 km |
| Jan 29, 1993 | 7 km WNW of Brownstown, Illinois | M3.2 | 78 km | 5 km |
| Apr 6, 1994 | 2 km NE of Tamaroa, Illinois | M3.2 | 148 km | 15 km |
| Jul 1, 2017 | 9 km SSE of Mulberry Grove, Illinois | M3.1 | 79 km | 17 km |
| Apr 24, 1990 | 5 km SW of Newton, Illinois | M2.9 | 147 km | 18 km |
| Sep 5, 2004 | 3 km WNW of Saint Peter, Illinois | M2.9 | 98 km | 33 km |
| Sep 5, 1995 | 3 km N of Woodlawn, Illinois | M2.9 | 133 km | 4 km |
| Apr 29, 2022 | 1 km SSW of Peerless Park, Missouri | M2.8 | 114 km | 8 km |
| Mar 28, 2024 | 1 km NNE of Germantown, Illinois | M2.8 | 95 km | 24 km |
| Sep 13, 1997 | 3 km SSE of Darmstadt, Illinois | M2.8 | 124 km | 16 km |
| May 5, 2008 | 3 km SSE of Fenton, Missouri | M2.8 | 114 km | 19 km |
| Sep 5, 2015 | 5 km SE of High Ridge, Missouri | M2.7 | 123 km | 8 km |
| Sep 19, 2024 | 1 km S of Old Monroe, Missouri | M2.6 | 97 km | 2 km |
| May 17, 2022 | 6 km NNW of Mount Vernon, Illinois | M2.5 | 137 km | 16 km |
| Jan 15, 1998 | 1 km SSE of Fenton, Missouri | M2.5 | 114 km | 16 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
664 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 30 fatalities, 647 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Apr 22, 2011 | EF4 | 94 km | 21.3 mi | 0 |
| Apr 3, 1981 | EF4 | 81 km | 11.9 mi | 0 |
| Mar 20, 1976 | EF4 | 97 km | 63.7 mi | 0 |
| Jun 14, 1957 | EF4 | 40 km | 4.3 mi | 2 |
| Dec 10, 2021 | EF3 | 75 km | 4.2 mi | 6 |
| Dec 1, 2018 | EF3 | 36 km | 12.5 mi | 0 |
| May 31, 2013 | EF3 | 73 km | 10.6 mi | 0 |
| Apr 19, 2011 | EF3 | 5 km | 4.3 mi | 0 |
| Dec 31, 2010 | EF3 | 65 km | 3.6 mi | 0 |
| Aug 19, 2009 | EF3 | 65 km | 24.3 mi | 0 |
| Jun 1, 1999 | EF3 | 15 km | 10.0 mi | 1 |
| Apr 19, 1996 | EF3 | 71 km | 14.5 mi | 0 |
| May 9, 1995 | EF3 | 54 km | 50.0 mi | 0 |
| Nov 15, 1988 | EF3 | 88 km | 9.0 mi | 0 |
| May 1, 1983 | EF3 | 41 km | 4.0 mi | 0 |
| May 1, 1983 | EF3 | 91 km | 16.0 mi | 0 |
| Dec 2, 1982 | EF3 | 98 km | 10.5 mi | 2 |
| Apr 7, 1980 | EF3 | 82 km | 7.3 mi | 0 |
| Jul 26, 1978 | EF3 | 45 km | 8.9 mi | 0 |
| Aug 21, 1977 | EF3 | 100 km | 26.9 mi | 6 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 28°F (-2°C) | 1.8 in | Coldest, Driest |
| February | 31°F (-1°C) | 2.0 in | |
| March | 42°F (6°C) | 3.4 in | |
| April | 53°F (12°C) | 3.8 in | |
| May | 64°F (18°C) | 4.3 in | Wettest |
| June | 72°F (22°C) | 3.9 in | |
| July | 76°F (25°C) | 3.7 in | Warmest |
| August | 74°F (23°C) | 3.4 in | |
| September | 67°F (20°C) | 3.3 in | |
| October | 56°F (13°C) | 2.7 in | |
| November | 43°F (6°C) | 3.2 in | |
| December | 31°F (-0°C) | 2.8 in |
Nilwood has a seasonal temperature swing of 48°F / from 28°F in January to 76°F in July. Total annual precipitation is 38.1 inches, with May being the wettest month (4.3") and January the driest (1.8").