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Weather & Climate in Portsmouth, OH
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Portsmouth experiences four distinct seasons with an average annual temperature of 55°F (13°C). Winters average 32°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 43.1 inches. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 963 feet.
Temperature
32°F Jan (0°C)
76°F Jul (25°C)
| Annual Average | 54.9°F |
| 2% above US avg | |
| January Average | 32°F (0°C) |
| July Average | 76°F (25°C) |
| Sunny Days | 293 days/yr |
Geography
| Elevation | 963 ft (294 m) |
| Area | 11.1 sq mi (28.7 km²) |
| Population Density | 1,670/sq mi |
| Coordinates | 38.7534°N, 82.9495°W |
| Timezone | America/New_York |
| County | Scioto County County |
| Nearest Airport | Greater Portsmouth Regional (PMH) 8 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 70.2 / 100 |
| Social Vulnerability | 49.5 / 100 |
| Community Resilience | 55.1 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively Moderate |
| Hail | Very Low |
| Strong Wind | Relatively Moderate |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively Moderate |
| Lightning | Relatively Moderate |
| Ice Storm | Relatively Moderate |
| Drought | Very Low |
| Cold Wave | Very Low |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
23 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.6.
| Feb 19, 1995 | 8 km SSE of Rocky Fork Point, Ohio | M3.6 | 61 km | 10 km |
| Nov 20, 2013 | 2 km SW of Buchtel, Ohio | M3.5 | 100 km | 8 km |
| May 24, 2017 | 1 km S of McArthur, Ohio | M3.4 | 67 km | 10 km |
| Apr 24, 2009 | 7 km ENE of Rio Grande, Ohio | M3.4 | 59 km | 8 km |
| Sep 8, 1990 | 5 km N of Owingsville, Kentucky | M3.3 | 94 km | 0 km |
| Feb 3, 2025 | 2 km NNW of Oak Hill, Ohio | M3.1 | 37 km | 26 km |
| Apr 25, 2020 | 2 km SE of South Shore, Kentucky | M2.9 | 5 km | 27 km |
| May 6, 2002 | 3 km SE of Racine, Ohio | M2.8 | 94 km | 5 km |
| Mar 17, 1999 | 2 km NNE of Ripley, Ohio | M2.8 | 77 km | 0 km |
| Jun 21, 2017 | 1 km SW of Pratt, West Virginia | M2.7 | 148 km | 17 km |
| May 11, 2015 | 5 km ESE of Maysville, Kentucky | M2.6 | 65 km | 11 km |
| Jun 6, 2014 | 13 km NNE of Sissonville, West Virginia | M2.6 | 119 km | 30 km |
| Mar 16, 2012 | 7 km SE of Alum Creek, West Virginia | M2.6 | 120 km | 5 km |
| Oct 2, 1998 | 10 km NE of Sylvester, West Virginia | M2.6 | 150 km | 0 km |
| Mar 8, 2016 | 0 km N of Thurman, Ohio | M2.6 | 47 km | 20 km |
| Feb 11, 2015 | 8 km SE of Richmond Dale, Ohio | M2.6 | 48 km | 20 km |
| Jul 23, 2013 | 6 km NNE of Germantown, Kentucky | M2.6 | 87 km | 4 km |
| Jan 28, 2024 | 3 km SW of Old Washington, Kentucky | M2.5 | 79 km | 15 km |
| Mar 27, 2013 | 3 km W of Apple Grove, West Virginia | M2.5 | 65 km | 15 km |
| Sep 27, 2009 | 22 km NNW of Hindman, Kentucky | M2.5 | 138 km | 7 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
241 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 10 fatalities, 236 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Apr 23, 1968 | EF5 | 14 km | 34.0 mi | 7 |
| May 10, 2003 | EF3 | 69 km | 25.0 mi | 0 |
| Oct 13, 1999 | EF3 | 94 km | 3.6 mi | 0 |
| Jun 30, 1993 | EF3 | 76 km | 15.0 mi | 0 |
| Apr 3, 1974 | EF3 | 57 km | 15.5 mi | 1 |
| Sep 3, 1970 | EF3 | 100 km | 2.3 mi | 0 |
| Apr 23, 1968 | EF3 | 4 km | 0.1 mi | 0 |
| May 7, 1967 | EF3 | 67 km | 2.0 mi | 0 |
| Nov 16, 1965 | EF3 | 95 km | 3.8 mi | 0 |
| Apr 8, 1965 | EF3 | 50 km | 6.9 mi | 0 |
| Apr 8, 1965 | EF3 | 13 km | 2.0 mi | 0 |
| Feb 10, 1959 | EF3 | 74 km | 10.5 mi | 0 |
| Apr 2, 2024 | EF2 | 55 km | 1.1 mi | 0 |
| Apr 2, 2024 | EF2 | 43 km | 1.9 mi | 0 |
| Jun 8, 2022 | EF2 | 72 km | 9.1 mi | 0 |
| Oct 15, 2021 | EF2 | 72 km | 0.9 mi | 0 |
| May 27, 2019 | EF2 | 87 km | 5.3 mi | 0 |
| Jul 4, 2016 | EF2 | 78 km | 2.6 mi | 0 |
| Mar 2, 2012 | EF2 | 50 km | 11.1 mi | 1 |
| Sep 16, 2010 | EF2 | 94 km | 3.3 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: UNNAMED (21,562 acres, 1987).
| Year | Name | Acres Burned | Distance |
| 1987 | UNNAMED | 21,562 | 98 km |
| 1987 | MILL CREEK ROAD | 7,029 | 92 km |
| 1987 | UNNAMED | 6,337 | 98 km |
| 1987 | PLUM BRANCH | 6,223 | 93 km |
| 2001 | UNNAMED | 5,981 | 99 km |
| 1991 | PRICHARD | 5,220 | 71 km |
| 1991 | UNNAMED | 4,451 | 91 km |
| 1987 | SUMMER FORK | 4,393 | 100 km |
| 1999 | UNNAMED | 3,373 | 86 km |
| 2009 | UNNAMED | 3,259 | 25 km |
| 1991 | DUNLOW | 3,074 | 92 km |
| 1995 | UNNAMED | 2,786 | 95 km |
| 1987 | UNNAMED | 2,559 | 70 km |
| 1987 | UNNAMED | 2,302 | 79 km |
| 1987 | KIAHS CREEK | 1,770 | 100 km |
| 1987 | TRACE BRANCH | 1,760 | 98 km |
| 1987 | UNNAMED | 1,683 | 69 km |
| 1991 | UNNAMED | 1,505 | 98 km |
| 2022 | 1170 DONITHON ROAD | 1,428 | 92 km |
| 2022 | 127 | 1,349 | 30 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 32°F (0°C) | 2.9 in | Coldest |
| February | 34°F (1°C) | 2.8 in | |
| March | 43°F (6°C) | 3.7 in | |
| April | 53°F (12°C) | 3.5 in | |
| May | 62°F (17°C) | 4.3 in | Wettest |
| June | 71°F (21°C) | 3.8 in | |
| July | 76°F (25°C) | 4.3 in | Warmest |
| August | 73°F (23°C) | 4.0 in | |
| September | 67°F (19°C) | 3.0 in | |
| October | 55°F (13°C) | 2.6 in | Driest |
| November | 45°F (7°C) | 3.1 in | |
| December | 36°F (2°C) | 3.4 in |
Portsmouth has a seasonal temperature swing of 44°F / from 32°F in January to 76°F in July. Total annual precipitation is 41.5 inches, with May being the wettest month (4.3") and October the driest (2.6").