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Weather & Climate in South Mount Vernon, OH
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
South Mount Vernon experiences four distinct seasons with an average annual temperature of 49°F (9°C). Winters average 24°F in January while summers reach 70°F in July. The area gets 282 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 1,018 feet.
Temperature
24°F Jan (-4°C)
70°F Jul (21°C)
| Annual Average | 48.5°F |
| 10% below US avg | |
| January Average | 24°F (-4°C) |
| July Average | 70°F (21°C) |
| Sunny Days | 282 days/yr |
Geography
| Elevation | 1,018 ft (310 m) |
| Area | 0.5 sq mi (1.3 km²) |
| Population Density | 1,404/sq mi |
| Coordinates | 40.3824°N, 82.5019°W |
| Timezone | America/New_York |
| County | Knox County County |
| Nearest Airport | Mansfield Lahm Regional (MFD) 30 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 61.0 / 100 |
| Social Vulnerability | 62.7 / 100 |
| Community Resilience | 80.1 / 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 | Relatively Low |
| Winter Weather | Relatively Moderate |
| Lightning | Relatively Moderate |
| Ice Storm | Relatively Moderate |
| Drought | No Rating |
| Cold Wave | Relatively Low |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
22 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.7.
| Mar 12, 2007 | Ohio | M3.7 | 137 km | 5 km |
| Nov 20, 2013 | 2 km SW of Buchtel, Ohio | M3.5 | 107 km | 8 km |
| Jun 3, 2017 | 1 km WNW of Batesville, Ohio | M3.4 | 115 km | 2 km |
| May 24, 2017 | 1 km S of McArthur, Ohio | M3.4 | 128 km | 10 km |
| Aug 31, 2011 | 3 km SE of Lowell, Ohio | M3.1 | 131 km | 5 km |
| Apr 22, 2025 | 3 km ESE of Buffalo, Ohio | M3.1 | 102 km | 5 km |
| Apr 24, 2025 | 3 km S of Pleasant City, Ohio | M3.1 | 99 km | 6 km |
| Apr 2, 2017 | 5 km W of Graysville, Ohio | M3.0 | 134 km | 4 km |
| Jun 5, 2011 | 5 km W of Lodi, Ohio | M3.0 | 80 km | 5 km |
| Mar 30, 2024 | 2 km SSW of Maple Ridge, Ohio | M3.0 | 135 km | 6 km |
| Aug 7, 2000 | 2 km S of Limaville, Ohio | M2.9 | 131 km | 5 km |
| May 9, 2025 | 3 km S of Pleasant City, Ohio | M2.9 | 100 km | 5 km |
| Apr 29, 2025 | 1 km SE of Pleasant City, Ohio | M2.8 | 99 km | 2 km |
| Feb 3, 2025 | 0 km NE of Reno, Ohio | M2.8 | 147 km | 10 km |
| May 12, 2006 | 2 km E of Lima, Ohio | M2.8 | 139 km | 5 km |
| May 17, 2010 | 2 km S of Boston Heights, Ohio | M2.7 | 127 km | 5 km |
| Nov 25, 1998 | 1 km SSW of New London, Ohio | M2.7 | 77 km | 5 km |
| May 14, 2010 | 1 km ENE of Gibsonburg, Ohio | M2.7 | 131 km | 5 km |
| Feb 11, 2015 | 8 km SE of Richmond Dale, Ohio | M2.6 | 139 km | 20 km |
| Feb 7, 2016 | 6 km W of Put-in-Bay, Ohio | M2.5 | 145 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
420 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 34 fatalities, 615 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Apr 11, 1965 | EF4 | 97 km | 22.0 mi | 18 |
| Nov 10, 2002 | EF3 | 89 km | 9.0 mi | 0 |
| Nov 10, 2002 | EF3 | 98 km | 21.0 mi | 1 |
| Oct 13, 1999 | EF3 | 96 km | 3.6 mi | 0 |
| May 31, 1985 | EF3 | 30 km | 29.0 mi | 1 |
| Jun 13, 1981 | EF3 | 36 km | 3.8 mi | 4 |
| Feb 22, 1971 | EF3 | 59 km | 6.8 mi | 0 |
| Sep 3, 1970 | EF3 | 91 km | 2.3 mi | 0 |
| Apr 11, 1965 | EF3 | 93 km | 15.0 mi | 4 |
| Jun 5, 2024 | EF2 | 43 km | 1.3 mi | 0 |
| Mar 14, 2024 | EF2 | 87 km | 19.5 mi | 0 |
| Mar 14, 2024 | EF2 | 72 km | 10.3 mi | 0 |
| Feb 28, 2024 | EF2 | 48 km | 14.0 mi | 0 |
| Jun 15, 2023 | EF2 | 94 km | 8.7 mi | 0 |
| May 27, 2019 | EF2 | 99 km | 5.3 mi | 0 |
| Apr 14, 2019 | EF2 | 53 km | 17.0 mi | 0 |
| Nov 5, 2017 | EF2 | 97 km | 0.6 mi | 0 |
| Nov 5, 2017 | EF2 | 46 km | 1.1 mi | 0 |
| Sep 4, 2017 | EF2 | 55 km | 16.7 mi | 0 |
| Apr 20, 2011 | EF2 | 40 km | 3.9 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 24°F (-4°C) | 2.3 in | Coldest |
| February | 28°F (-3°C) | 2.2 in | Driest |
| March | 38°F (3°C) | 3.3 in | |
| April | 48°F (9°C) | 3.6 in | |
| May | 58°F (15°C) | 4.2 in | |
| June | 67°F (20°C) | 4.1 in | |
| July | 70°F (21°C) | 4.3 in | Warmest, Wettest |
| August | 70°F (21°C) | 3.7 in | |
| September | 63°F (17°C) | 3.4 in | |
| October | 52°F (11°C) | 2.5 in | |
| November | 41°F (5°C) | 3.4 in | |
| December | 31°F (-1°C) | 3.0 in |
South Mount Vernon has a seasonal temperature swing of 46°F / from 24°F in January to 70°F in July. Total annual precipitation is 40.0 inches, with July being the wettest month (4.3") and February the driest (2.2").