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Weather & Climate in Arnold, MD
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Arnold enjoys a temperate climate with an average annual temperature of 56°F (13°C). Winters average 34°F in January while summers reach 78°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 45.0 inches. The area receives 19.3 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 41. The city sits at an elevation of 60 feet.
Temperature
34°F Jan (1°C)
78°F Jul (26°C)
| Annual Average | 56.2°F |
| 4% above US avg | |
| January Average | 34°F (1°C) |
| July Average | 78°F (26°C) |
| Sunny Days | 293 days/yr |
Geography
| Elevation | 60 ft (18 m) |
| Area | 10.8 sq mi (28.0 km²) |
| Population Density | 2,206/sq mi |
| Coordinates | 39.0432°N, 76.5050°W |
| Timezone | America/New_York |
| County | Baltimore city County |
| Nearest Airport | Baltimore/Washington International Thurgood Marshall (BWI) 13 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 41.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively High |
| Risk Score | 95.0 / 100 |
| Social Vulnerability | 74.1 / 100 |
| Community Resilience | 78.8 / 100 |
Hazard Breakdown
| Tornado | Relatively High |
| Hurricane | Relatively Moderate |
| Earthquake | Relatively Moderate |
| Wildfire | Very Low |
| Flood | Relatively High |
| Hail | Relatively Moderate |
| Strong Wind | Relatively High |
| Heat Wave | Relatively High |
| Winter Weather | Very High |
| Lightning | Relatively High |
| Ice Storm | Relatively Moderate |
| Drought | No Rating |
| Cold Wave | Relatively High |
| Landslide | Very Low |
| Coastal Flood | Relatively Moderate |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
27 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.6.
| Jan 16, 1994 | 2 km W of Sinking Spring, Pennsylvania | M4.6 | 149 km | 5 km |
| Jan 16, 1994 | 0 km E of Sinking Spring, Pennsylvania | M4.2 | 149 km | 5 km |
| Jul 16, 2010 | 5 km NNW of Barnesville, Maryland | M3.6 | 82 km | 7 km |
| Oct 23, 1990 | 3 km W of Hancocks Bridge, New Jersey | M3.2 | 101 km | 10 km |
| Jun 3, 2010 | 4 km ENE of Franklintown, Pennsylvania | M3.1 | 123 km | 2 km |
| Jan 17, 2016 | 3 km NE of Ranson, West Virginia | M3.0 | 118 km | 5 km |
| Nov 14, 1997 | 0 km S of Rothsville, Pennsylvania | M3.0 | 125 km | 5 km |
| Apr 24, 2009 | 1 km S of Franklintown, Pennsylvania | M2.9 | 122 km | 1 km |
| Jan 16, 1994 | 0 km SSE of Sinking Spring, Pennsylvania | M2.9 | 148 km | 5 km |
| Sep 15, 2019 | 5 km ESE of East Berlin, Pennsylvania | M2.8 | 104 km | 5 km |
| Jul 1, 2009 | 3 km ESE of Pennsville, New Jersey | M2.8 | 110 km | 5 km |
| Oct 25, 2009 | 4 km ENE of Franklintown, Pennsylvania | M2.8 | 124 km | 1 km |
| Mar 15, 1993 | 5 km W of Columbia, Maryland | M2.7 | 40 km | 5 km |
| Oct 28, 1994 | 1 km E of Mount Vernon, Maryland | M2.7 | 30 km | — |
| Mar 11, 1995 | 0 km ENE of Landisville, Pennsylvania | M2.7 | 118 km | 5 km |
| Jan 25, 2015 | 4 km ESE of Downingtown, Pennsylvania | M2.6 | 129 km | 2 km |
| Jan 13, 1990 | 6 km ENE of Eldersburg, Maryland | M2.6 | 53 km | 5 km |
| Jun 25, 2021 | 2 km SE of Woodlawn, Maryland | M2.6 | 34 km | 3 km |
| Jan 18, 1994 | 3 km SE of Clay, Pennsylvania | M2.6 | 130 km | 5 km |
| Oct 28, 1996 | 2 km W of Reinholds, Pennsylvania | M2.6 | 140 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Hurricane History
7 hurricanes (Category 1+) recorded within 500 km since 1980. Strongest on record: Category 3.
| Year | Name | Category | Max Wind | Closest |
| 2012 | Sandy | Category 1 | 92 mph | 299 km |
| 2011 | Irene | Category 1 | 75 mph | 168 km |
| 2003 | Isabel | Category 1 | 75 mph | 281 km |
| 1999 | Floyd | Category 1 | — | 252 km |
| 1991 | Bob | Category 3 | 115 mph | 285 km |
| 1986 | Charley | Category 1 | 81 mph | 215 km |
| 1985 | Gloria | Category 2 | 98 mph | 188 km |
Source: NOAA IBTrACS (Category 1+, 1980–2026).
Tornado History
466 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 13 fatalities, 465 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Apr 28, 2002 | EF4 | 80 km | 38.0 mi | 3 |
| Apr 1, 2023 | EF3 | 81 km | 14.3 mi | 1 |
| Apr 28, 2002 | EF3 | 72 km | 18.0 mi | 0 |
| Sep 24, 2001 | EF3 | 43 km | 17.5 mi | 2 |
| Jul 19, 1996 | EF3 | 65 km | 2.2 mi | 0 |
| Jul 27, 1994 | EF3 | 99 km | 4.0 mi | 0 |
| May 22, 1983 | EF3 | 97 km | 2.0 mi | 0 |
| Sep 5, 1979 | EF3 | 58 km | 17.9 mi | 1 |
| Jan 26, 1978 | EF3 | 92 km | 0.7 mi | 1 |
| Apr 1, 1973 | EF3 | 76 km | 9.8 mi | 0 |
| Jun 9, 1961 | EF3 | 20 km | 0.1 mi | 0 |
| Apr 5, 1952 | EF3 | 94 km | 17.5 mi | 0 |
| Sep 1, 2021 | EF2 | 93 km | 5.9 mi | 0 |
| Sep 1, 2021 | EF2 | 23 km | 11.4 mi | 0 |
| Aug 4, 2020 | EF2 | 93 km | 1.3 mi | 0 |
| Aug 4, 2020 | EF2 | 87 km | 35.8 mi | 0 |
| Apr 15, 2019 | EF2 | 95 km | 6.2 mi | 0 |
| Nov 2, 2018 | EF2 | 67 km | 5.5 mi | 0 |
| Jul 23, 2017 | EF2 | 16 km | 2.4 mi | 0 |
| Sep 18, 2004 | EF2 | 74 km | 2.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Tsunami History
1 tsunami recorded within 500 km.
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1840 | PHILADELPHIA, PENNSYLVANIA | Earthquake | — | — | 140 km |
Source: NOAA/NCEI Historical Tsunami Database.
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: BESTPITCH (7,743 acres, 2017).
| Year | Name | Acres Burned | Distance |
| 2017 | BESTPITCH | 7,743 | 85 km |
| 2004 | RETAINING ECOLOGICAL HEALTH | 5,678 | 82 km |
| 2014 | BLACKWATER MARSH WUI BURNS FY14 | 5,433 | 83 km |
| 2005 | MARSH RX-FWS | 4,380 | 82 km |
| 2007 | GUINEA MARSH | 4,173 | 88 km |
| 2009 | DOCTORS CREEK | 3,686 | 87 km |
| 1999 | FB R O C I | 3,525 | 85 km |
| 2019 | MDBWR-FY19-RX-MDWHS SUPPORT | 3,197 | 83 km |
| 2011 | COMPARTMENT J | 2,775 | 83 km |
| 2005 | ISLAND CREEK | 2,729 | 89 km |
| 2004 | UNNAMED | 2,156 | 89 km |
| 1992 | UNNAMED | 2,038 | 84 km |
| 2005 | VEGETATION RESEARCH | 1,926 | 83 km |
| 2011 | THOROFARE | 1,850 | 83 km |
| 1987 | UNNAMED | 1,692 | 80 km |
| 2004 | ROBBINS FIRE | 1,612 | 86 km |
| 2004 | BLACKWATER HAZARD FUEL REDUCTION | 1,518 | 75 km |
| 2009 | BECKERS ISLAND | 1,398 | 85 km |
| 2022 | ELLIOTTS ISLAND | 1,324 | 89 km |
| 1991 | KENTIS WEST | 1,273 | 96 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 34°F (1°C) | 3.4 in | Coldest |
| February | 36°F (2°C) | 2.9 in | Driest |
| March | 44°F (7°C) | 4.0 in | |
| April | 54°F (12°C) | 3.4 in | |
| May | 64°F (18°C) | 4.3 in | Wettest |
| June | 72°F (22°C) | 3.7 in | |
| July | 78°F (26°C) | 4.1 in | Warmest |
| August | 76°F (24°C) | 4.1 in | |
| September | 69°F (20°C) | 3.9 in | |
| October | 57°F (14°C) | 3.2 in | |
| November | 48°F (9°C) | 3.5 in | |
| December | 39°F (4°C) | 3.5 in |
Arnold has a seasonal temperature swing of 44°F / from 34°F in January to 78°F in July. Total annual precipitation is 44.1 inches, with May being the wettest month (4.3") and February the driest (2.9").