Weather & Climate in Chillum, MD
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Chillum enjoys a temperate climate with an average annual temperature of 59°F (15°C). Winters average 38°F in January while summers reach 81°F in July. Annual precipitation totals 41.8 inches. The area receives 13.7 inches of snow annually. Air quality is rated Good with a median AQI of 39. 77% of days have good air quality. The city sits at an elevation of 59 feet.
Temperature
38°F Jan (3°C)
81°F Jul (27°C)
| Annual Average | 59.3°F |
| 10% above US avg | |
| January Average | 38°F (3°C) |
| July Average | 81°F (27°C) |
Geography
| Elevation | 59 ft (18 m) |
| Area | 3.4 sq mi (8.8 km²) |
| Population Density | 10,403/sq mi |
| Coordinates | 38.9667°N, 76.9789°W |
| Timezone | America/New_York |
| County | Prince George's County County |
| Nearest Airport | Ronald Reagan Washington Ntl (DCA) 9 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 39.0 |
| Rating | Good |
| Good Days % | 76.5% |
| Unhealthy Days | 3 |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 93.2 / 100 |
| Social Vulnerability | 49.4 / 100 |
| Community Resilience | 29.8 / 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 | Very High |
| Ice Storm | Relatively Moderate |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Moderate |
| Landslide | Relatively Moderate |
| Coastal Flood | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
40 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M5.8.
| Aug 23, 2011 | 11 km SSW of Mineral, Virginia | M5.8 | 144 km | 6 km |
| Aug 25, 2011 | 8 km SW of Mineral, Virginia | M4.5 | 142 km | 7 km |
| Aug 24, 2011 | 11 km SSW of Mineral, Virginia | M4.2 | 145 km | 0 km |
| Jul 16, 2010 | 5 km NNW of Barnesville, Maryland | M3.6 | 50 km | 7 km |
| Sep 1, 2011 | 7 km SSW of Mineral, Virginia | M3.4 | 140 km | 3 km |
| Oct 23, 1990 | 3 km W of Hancocks Bridge, New Jersey | M3.2 | 141 km | 10 km |
| Jan 30, 2012 | 9 km SSE of Louisa, Virginia | M3.1 | 143 km | 3 km |
| Jun 3, 2010 | 4 km ENE of Franklintown, Pennsylvania | M3.1 | 125 km | 2 km |
| Jan 17, 2016 | 3 km NE of Ranson, West Virginia | M3.0 | 83 km | 5 km |
| Oct 2, 2010 | 10 km NNW of Ashland, Virginia | M3.0 | 132 km | 19 km |
| Oct 12, 2011 | 9 km S of Louisa, Virginia | M3.0 | 144 km | 4 km |
| Nov 14, 1997 | 0 km S of Rothsville, Pennsylvania | M3.0 | 145 km | 5 km |
| Mar 26, 2012 | 13 km S of Louisa, Virginia | M3.0 | 147 km | 9 km |
| Apr 24, 2009 | 1 km S of Franklintown, Pennsylvania | M2.9 | 122 km | 1 km |
| Sep 15, 2019 | 5 km ESE of East Berlin, Pennsylvania | M2.8 | 107 km | 5 km |
| Mar 15, 2015 | 6 km SW of Mineral, Virginia | M2.8 | 140 km | 5 km |
| Aug 23, 2011 | 9 km SSW of Mineral, Virginia | M2.8 | 142 km | 0 km |
| Jul 1, 2009 | 3 km ESE of Pennsville, New Jersey | M2.8 | 149 km | 5 km |
| Oct 25, 2009 | 4 km ENE of Franklintown, Pennsylvania | M2.8 | 126 km | 1 km |
| Feb 19, 2012 | 12 km S of Louisa, Virginia | M2.7 | 146 km | 3 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Hurricane History
5 hurricanes (Category 1+) recorded within 500 km since 1980. Strongest on record: Category 2.
| Year | Name | Category | Max Wind | Closest |
| 2011 | Irene | Category 1 | 75 mph | 197 km |
| 2003 | Isabel | Category 1 | 75 mph | 260 km |
| 1999 | Floyd | Category 1 | - | 253 km |
| 1986 | Charley | Category 1 | 81 mph | 234 km |
| 1985 | Gloria | Category 2 | 98 mph | 224 km |
Source: NOAA IBTrACS (Category 1+, 1980-2026).
Tornado History
481 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 9 fatalities, 369 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Apr 28, 2002 | EF4 | 50 km | 38.0 mi | 3 |
| Sep 24, 2001 | EF4 | 97 km | 10.0 mi | 0 |
| Sep 17, 2004 | EF3 | 87 km | 9.0 mi | 0 |
| Apr 28, 2002 | EF3 | 85 km | 18.0 mi | 0 |
| Sep 24, 2001 | EF3 | 4 km | 17.5 mi | 2 |
| Jul 19, 1996 | EF3 | 59 km | 2.2 mi | 0 |
| May 22, 1983 | EF3 | 85 km | 2.0 mi | 0 |
| Sep 5, 1979 | EF3 | 23 km | 17.9 mi | 1 |
| Jan 26, 1978 | EF3 | 59 km | 0.7 mi | 1 |
| Apr 1, 1973 | EF3 | 36 km | 9.8 mi | 0 |
| Jun 9, 1961 | EF3 | 40 km | 0.1 mi | 0 |
| Apr 5, 1952 | EF3 | 93 km | 17.5 mi | 0 |
| Sep 1, 2021 | EF2 | 36 km | 11.4 mi | 0 |
| Nov 2, 2018 | EF2 | 46 km | 5.5 mi | 0 |
| Jul 23, 2017 | EF2 | 55 km | 2.4 mi | 0 |
| May 8, 2008 | EF2 | 82 km | 3.4 mi | 0 |
| Sep 18, 2004 | EF2 | 97 km | 2.0 mi | 0 |
| Sep 17, 2004 | EF2 | 73 km | 13.0 mi | 0 |
| Sep 17, 2004 | EF2 | 79 km | 8.0 mi | 0 |
| Sep 17, 2004 | EF2 | 69 km | 3.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950-2024, US only).
Wildfire History
5 wildfires (100+ acres) recorded within 100 km. Largest: BLACKWATER HAZARD FUEL REDUCTION (1,518 acres, 2004).
| Year | Name | Acres Burned | Distance |
| 2004 | BLACKWATER HAZARD FUEL REDUCTION | 1,518 | 95 km |
| 2011 | COMPARTMENT E42 AND 43 | 991 | 99 km |
| 1999 | NCO | 816 | 58 km |
| 2001 | A 1 M 2 | 594 | 95 km |
| 2005 | A 1 | 561 | 95 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 38°F (3°C) | 2.9 in | Coldest |
| February | 40°F (4°C) | 2.6 in | Driest |
| March | 48°F (9°C) | 3.5 in | |
| April | 58°F (15°C) | 3.2 in | |
| May | 67°F (20°C) | 3.9 in | |
| June | 76°F (25°C) | 4.2 in | |
| July | 81°F (27°C) | 4.3 in | Warmest, Wettest |
| August | 79°F (26°C) | 3.3 in | |
| September | 72°F (22°C) | 3.9 in | |
| October | 61°F (16°C) | 3.7 in | |
| November | 50°F (10°C) | 2.9 in | |
| December | 42°F (5°C) | 3.4 in |
Chillum has a seasonal temperature swing of 44°F / from 38°F in January to 81°F in July. Total annual precipitation is 41.8 inches, with July being the wettest month (4.3") and February the driest (2.6").