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Weather & Climate in San Mar, MD
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
San Mar experiences four distinct seasons with an average annual temperature of 54°F (12°C). Winters average 31°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 43.6 inches. Air quality is rated Good with a median AQI of 41. The city sits at an elevation of 567 feet.
Temperature
31°F Jan (-0°C)
76°F Jul (25°C)
| Annual Average | 54.2°F |
| 0% below US avg | |
| January Average | 31°F (-0°C) |
| July Average | 76°F (25°C) |
| Sunny Days | 293 days/yr |
Geography
| Elevation | 567 ft (173 m) |
| Area | 0.5 sq mi (1.2 km²) |
| Population Density | 921/sq mi |
| Coordinates | 39.5522°N, 77.6409°W |
| Timezone | America/New_York |
| County | Washington County County |
| Nearest Airport | Hagerstown Regional/Richard A Henson Field (HGR) 12 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 41.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 68.8 / 100 |
| Social Vulnerability | 44.6 / 100 |
| Community Resilience | 73.2 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Relatively Moderate |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively Moderate |
| Hail | Relatively Low |
| Strong Wind | Relatively Moderate |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively Moderate |
| Lightning | Relatively Moderate |
| Ice Storm | Relatively Low |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Low |
| Landslide | Relatively Low |
| Avalanche | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
18 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.6.
| Jul 16, 2010 | 5 km NNW of Barnesville, Maryland | M3.6 | 38 km | 7 km |
| Jun 13, 2019 | 9 km N of Blain, Pennsylvania | M3.4 | 97 km | 27 km |
| Jun 3, 2010 | 4 km ENE of Franklintown, Pennsylvania | M3.1 | 82 km | 2 km |
| Jan 17, 2016 | 3 km NE of Ranson, West Virginia | M3.0 | 31 km | 5 km |
| Nov 14, 1997 | 0 km S of Rothsville, Pennsylvania | M3.0 | 136 km | 5 km |
| Apr 24, 2009 | 1 km S of Franklintown, Pennsylvania | M2.9 | 77 km | 1 km |
| Sep 15, 2019 | 5 km ESE of East Berlin, Pennsylvania | M2.8 | 75 km | 5 km |
| Oct 25, 2009 | 4 km ENE of Franklintown, Pennsylvania | M2.8 | 83 km | 1 km |
| Mar 15, 1993 | 5 km W of Columbia, Maryland | M2.7 | 73 km | 5 km |
| Oct 28, 1994 | 1 km E of Mount Vernon, Maryland | M2.7 | 94 km | — |
| Mar 11, 1995 | 0 km ENE of Landisville, Pennsylvania | M2.7 | 122 km | 5 km |
| Jan 13, 1990 | 6 km ENE of Eldersburg, Maryland | M2.6 | 67 km | 5 km |
| Jun 25, 2021 | 2 km SE of Woodlawn, Maryland | M2.6 | 85 km | 3 km |
| Jan 18, 1994 | 3 km SE of Clay, Pennsylvania | M2.6 | 140 km | 5 km |
| Sep 29, 1997 | Virginia | M2.5 | 84 km | 3 km |
| Jul 27, 1997 | 5 km SSE of Culpeper, Virginia | M2.5 | 128 km | 19 km |
| Mar 10, 1993 | 3 km WSW of Columbia, Maryland | M2.5 | 74 km | 5 km |
| Jun 25, 2001 | 8 km S of Remington, Virginia | M2.5 | 123 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Hurricane History
1 hurricane (Category 1+) recorded within 500 km since 1980. Strongest on record: Category 1.
| Year | Name | Category | Max Wind | Closest |
| 2011 | Irene | Category 1 | 75 mph | 280 km |
Source: NOAA IBTrACS (Category 1+, 1980–2026).
Tornado History
384 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 5 fatalities, 231 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Sep 24, 2001 | EF3 | 90 km | 17.5 mi | 2 |
| Jul 19, 1996 | EF3 | 57 km | 2.2 mi | 0 |
| May 22, 1983 | EF3 | 37 km | 2.0 mi | 0 |
| Jun 7, 1980 | EF3 | 68 km | 1.5 mi | 0 |
| Sep 5, 1979 | EF3 | 99 km | 17.9 mi | 1 |
| Apr 1, 1973 | EF3 | 88 km | 9.8 mi | 0 |
| Jun 9, 1961 | EF3 | 96 km | 0.1 mi | 0 |
| Apr 16, 1961 | EF3 | 56 km | 0.1 mi | 0 |
| Apr 5, 1952 | EF3 | 63 km | 17.5 mi | 0 |
| Apr 19, 2019 | EF2 | 43 km | 2.9 mi | 0 |
| Nov 2, 2018 | EF2 | 46 km | 5.5 mi | 0 |
| Apr 28, 2011 | EF2 | 87 km | 2.6 mi | 0 |
| Sep 17, 2004 | EF2 | 39 km | 2.0 mi | 0 |
| Sep 17, 2004 | EF2 | 83 km | 15.0 mi | 0 |
| Sep 17, 2004 | EF2 | 62 km | 5.0 mi | 0 |
| Sep 17, 2004 | EF2 | 95 km | 13.0 mi | 0 |
| Sep 17, 2004 | EF2 | 19 km | 3.0 mi | 0 |
| Sep 24, 2001 | EF2 | 60 km | 5.0 mi | 0 |
| Jul 19, 1996 | EF2 | 20 km | 2.0 mi | 0 |
| Jun 24, 1996 | EF2 | 79 km | 20.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
4 wildfires (100+ acres) recorded within 100 km. Largest: SMITH RUN FIRE (1,908 acres, 2011).
| Year | Name | Acres Burned | Distance |
| 2011 | SMITH RUN FIRE | 1,908 | 95 km |
| 2012 | POINT 2 | 1,126 | 96 km |
| 2014 | BEAR DEN | 945 | 94 km |
| 1984 | UNNAMED | 696 | 90 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 31°F (-0°C) | 2.8 in | Coldest |
| February | 32°F (-0°C) | 2.7 in | Driest |
| March | 41°F (5°C) | 3.4 in | |
| April | 51°F (10°C) | 3.5 in | |
| May | 61°F (16°C) | 4.2 in | Wettest |
| June | 69°F (21°C) | 4.0 in | |
| July | 76°F (25°C) | 3.6 in | Warmest |
| August | 72°F (22°C) | 3.5 in | |
| September | 65°F (19°C) | 3.6 in | |
| October | 54°F (12°C) | 3.4 in | |
| November | 44°F (7°C) | 3.5 in | |
| December | 34°F (1°C) | 3.0 in |
San Mar has a seasonal temperature swing of 45°F / from 31°F in January to 76°F in July. Total annual precipitation is 41.3 inches, with May being the wettest month (4.2") and February the driest (2.7").