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Weather & Climate in Clayton, IL
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Clayton experiences four distinct seasons with an average annual temperature of 52°F (11°C). Winters average 25°F in January while summers reach 75°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 40.9 inches. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 731 feet.
Temperature
25°F Jan (-4°C)
75°F Jul (24°C)
| Annual Average | 51.7°F |
| 4% below US avg | |
| January Average | 25°F (-4°C) |
| July Average | 75°F (24°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 731 ft (223 m) |
| Area | 0.3 sq mi (0.9 km²) |
| Population Density | 678/sq mi |
| Coordinates | 40.0306°N, 90.9580°W |
| Timezone | America/Chicago |
| County | Schuyler County County |
| Nearest Airport | Quincy Regional-Baldwin Field (UIN) 14 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 11.4 / 100 |
| Social Vulnerability | 71.6 / 100 |
| Community Resilience | 63.1 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Very Low |
| Hail | Relatively Low |
| Strong Wind | Relatively Moderate |
| Heat Wave | Relatively Low |
| Winter Weather | Very Low |
| Lightning | Very Low |
| Ice Storm | Very Low |
| Drought | Relatively Low |
| Cold Wave | Relatively Low |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
2 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M2.9.
| Feb 8, 2004 | 6 km SSW of Stoutsville, Missouri | M2.9 | 99 km | 5 km |
| Sep 19, 2024 | 1 km S of Old Monroe, Missouri | M2.6 | 125 km | 2 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
446 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 10 fatalities, 402 injuries.
| Date | Rating | Distance | Path | Fatalities |
| May 13, 1995 | EF4 | 68 km | 50.0 mi | 0 |
| May 13, 1995 | EF4 | 67 km | 7.0 mi | 0 |
| Apr 4, 2023 | EF3 | 63 km | 19.9 mi | 0 |
| Dec 31, 2010 | EF3 | 94 km | 3.6 mi | 0 |
| May 10, 2003 | EF3 | 77 km | 12.0 mi | 0 |
| Apr 8, 1999 | EF3 | 55 km | 7.5 mi | 0 |
| May 13, 1995 | EF3 | 97 km | 25.0 mi | 0 |
| Jun 21, 1981 | EF3 | 36 km | 8.8 mi | 1 |
| Jul 23, 1975 | EF3 | 89 km | 14.0 mi | 2 |
| Jul 23, 1975 | EF3 | 79 km | 11.1 mi | 0 |
| Jun 13, 1975 | EF3 | 94 km | 6.6 mi | 0 |
| Apr 13, 1974 | EF3 | 52 km | 11.0 mi | 0 |
| Sep 30, 1973 | EF3 | 22 km | 0.1 mi | 0 |
| May 1, 1973 | EF3 | 79 km | 3.6 mi | 2 |
| May 15, 1968 | EF3 | 98 km | 12.6 mi | 0 |
| Jan 24, 1967 | EF3 | 77 km | 4.3 mi | 1 |
| Jan 24, 1967 | EF3 | 64 km | 5.1 mi | 1 |
| Aug 25, 1965 | EF3 | 98 km | 3.0 mi | 0 |
| Apr 21, 1964 | EF3 | 47 km | 14.1 mi | 0 |
| Apr 22, 1963 | EF3 | 97 km | 42.9 mi | 1 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 25°F (-4°C) | 1.4 in | Coldest, Driest |
| February | 29°F (-2°C) | 1.5 in | |
| March | 41°F (5°C) | 3.0 in | |
| April | 52°F (11°C) | 3.9 in | |
| May | 63°F (17°C) | 4.5 in | Wettest |
| June | 72°F (22°C) | 3.8 in | |
| July | 75°F (24°C) | 4.3 in | Warmest |
| August | 74°F (23°C) | 3.5 in | |
| September | 66°F (19°C) | 4.1 in | |
| October | 55°F (13°C) | 3.1 in | |
| November | 41°F (5°C) | 3.0 in | |
| December | 29°F (-1°C) | 2.3 in |
Clayton has a seasonal temperature swing of 50°F / from 25°F in January to 75°F in July. Total annual precipitation is 38.2 inches, with May being the wettest month (4.5") and January the driest (1.4").