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Weather & Climate in Aldan, PA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Aldan enjoys a temperate climate with an average annual temperature of 56°F (14°C). Winters average 34°F in January while summers reach 79°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 44.1 inches. The area receives 23.1 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 40. The city sits at an elevation of 130 feet.
Temperature
34°F Jan (1°C)
79°F Jul (26°C)
| Annual Average | 56.3°F |
| 4% above US avg | |
| January Average | 34°F (1°C) |
| July Average | 79°F (26°C) |
| Sunny Days | 293 days/yr |
Geography
| Elevation | 130 ft (40 m) |
| Area | 0.2 sq mi (0.6 km²) |
| Population Density | 7,032/sq mi |
| Coordinates | 39.9224°N, 75.2881°W |
| Timezone | America/New_York |
| County | Delaware County County |
| Nearest Airport | Philadelphia International (PHL) 4 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 40.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 92.9 / 100 |
| Social Vulnerability | 33.0 / 100 |
| Community Resilience | 84.3 / 100 |
Hazard Breakdown
| Tornado | Relatively High |
| Hurricane | Relatively Moderate |
| Earthquake | Relatively Moderate |
| Wildfire | Very Low |
| Flood | Relatively High |
| Hail | Very Low |
| Strong Wind | Relatively High |
| Heat Wave | Relatively High |
| Winter Weather | Very High |
| Lightning | Relatively High |
| Ice Storm | Relatively High |
| Drought | Relatively Low |
| Cold Wave | Relatively High |
| Landslide | Very Low |
| Coastal Flood | Relatively Moderate |
| Avalanche | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
35 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.8.
| Apr 5, 2024 | 2024 Tewksbury, New Jersey Earthquake | M4.8 | 97 km | 3 km |
| Jan 16, 1994 | 2 km W of Sinking Spring, Pennsylvania | M4.6 | 78 km | 5 km |
| Jan 16, 1994 | 0 km E of Sinking Spring, Pennsylvania | M4.2 | 76 km | 5 km |
| Apr 5, 2024 | 7 km WSW of Gladstone, New Jersey | M3.7 | 97 km | 4 km |
| Oct 23, 1990 | 3 km W of Hancocks Bridge, New Jersey | M3.2 | 49 km | 10 km |
| Aug 26, 2003 | 4 km NNW of Milford, New Jersey | M3.1 | 78 km | 3 km |
| Jan 9, 1992 | 4 km WNW of Robertsville, New Jersey | M3.1 | 94 km | 8 km |
| Jun 3, 2010 | 4 km ENE of Franklintown, Pennsylvania | M3.1 | 145 km | 2 km |
| Aug 3, 2025 | 0 km W of Little Ferry, New Jersey | M3.0 | 147 km | 10 km |
| Nov 14, 1997 | 0 km S of Rothsville, Pennsylvania | M3.0 | 86 km | 5 km |
| Feb 3, 2009 | 1 km ESE of Victory Gardens, New Jersey | M3.0 | 124 km | 0 km |
| Apr 24, 2009 | 1 km S of Franklintown, Pennsylvania | M2.9 | 149 km | 1 km |
| May 24, 2024 | 6 km E of Califon, New Jersey | M2.9 | 99 km | 7 km |
| Apr 27, 2024 | 7 km WSW of Gladstone, New Jersey | M2.9 | 97 km | 5 km |
| Jan 16, 1994 | 0 km SSE of Sinking Spring, Pennsylvania | M2.9 | 76 km | 5 km |
| Sep 15, 2019 | 5 km ESE of East Berlin, Pennsylvania | M2.8 | 139 km | 5 km |
| May 10, 1993 | 1 km NW of Whitfield, Pennsylvania | M2.8 | 78 km | 5 km |
| Jul 1, 2009 | 3 km ESE of Pennsville, New Jersey | M2.8 | 35 km | 5 km |
| Oct 25, 2009 | 4 km ENE of Franklintown, Pennsylvania | M2.8 | 145 km | 1 km |
| Oct 28, 1994 | 1 km E of Mount Vernon, Maryland | M2.7 | 132 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 3.
| Year | Name | Category | Max Wind | Closest |
| 2012 | Sandy | Category 2 | 92 mph | 255 km |
| 2011 | Irene | Category 1 | 75 mph | 204 km |
| 1991 | Bob | Category 3 | 109 mph | 227 km |
| 1986 | Charley | Category 1 | 75 mph | 281 km |
| 1985 | Gloria | Category 2 | 98 mph | 144 km |
Source: NOAA IBTrACS (Category 1+, 1980–2026).
Tornado History
359 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 10 fatalities, 275 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Sep 1, 2021 | EF3 | 28 km | 12.4 mi | 0 |
| Jul 29, 2021 | EF3 | 33 km | 3.4 mi | 0 |
| May 31, 1998 | EF3 | 81 km | 8.3 mi | 0 |
| Jul 27, 1994 | EF3 | 40 km | 2.0 mi | 3 |
| Jul 27, 1994 | EF3 | 47 km | 4.0 mi | 0 |
| Oct 18, 1990 | EF3 | 76 km | 0.5 mi | 0 |
| Jul 21, 1983 | EF3 | 91 km | 0.2 mi | 0 |
| Jul 26, 1981 | EF3 | 97 km | 3.3 mi | 0 |
| Sep 26, 1977 | EF3 | 82 km | 5.9 mi | 0 |
| Apr 28, 1961 | EF3 | 37 km | 0.3 mi | 0 |
| Jun 24, 1960 | EF3 | 59 km | 12.9 mi | 0 |
| Mar 22, 1955 | EF3 | 29 km | 9.6 mi | 1 |
| Nov 4, 1950 | EF3 | 77 km | 15.9 mi | 0 |
| Apr 1, 2023 | EF2 | 80 km | 2.1 mi | 0 |
| Apr 1, 2023 | EF2 | 90 km | 1.6 mi | 0 |
| Feb 21, 2023 | EF2 | 64 km | 5.8 mi | 0 |
| Sep 1, 2021 | EF2 | 61 km | 5.9 mi | 0 |
| Sep 1, 2021 | EF2 | 21 km | 8.3 mi | 1 |
| Jul 29, 2021 | EF2 | 96 km | 4.2 mi | 0 |
| Jul 29, 2021 | EF2 | 55 km | 6.3 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Tsunami History
2 tsunamis recorded within 500 km.
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1895 | HIGH BRIDGE, NJ | Earthquake | — | — | 90 km |
| 1840 | PHILADELPHIA, PENNSYLVANIA | Earthquake | — | — | 16 km |
Source: NOAA/NCEI Historical Tsunami Database.
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: GREENWOOD STATE FOREST (21,271 acres, 1995).
| Year | Name | Acres Burned | Distance |
| 1995 | GREENWOOD STATE FOREST | 21,271 | 87 km |
| 2007 | WARREN GROVE | 15,315 | 85 km |
| 2022 | MULLICA RIVER FIRE | 13,082 | 58 km |
| 1999 | BASS RIVER | 12,129 | 77 km |
| 2019 | SPRING HILL FIRE | 8,182 | 73 km |
| 2023 | ALLEN ROAD | 6,213 | 76 km |
| 1992 | FORKED RIVER MOUTAIN APR | 5,093 | 86 km |
| 1992 | POWER PLANT | 4,928 | 91 km |
| 1992 | UNNAMED | 4,470 | 67 km |
| 2024 | TEA TIME HILL | 4,444 | 61 km |
| 2006 | UNNAMED | 3,780 | 61 km |
| 2017 | PENN SWAMP FIRE | 3,587 | 62 km |
| 2023 | JIMMYS WATER HOLE | 3,585 | 78 km |
| 1989 | SIMM PLACE | 3,262 | 75 km |
| 2002 | UNNAMED | 2,824 | 67 km |
| 2007 | ATSION | 2,705 | 54 km |
| 1992 | FOUR MILE COLONY | 2,647 | 63 km |
| 1996 | UNNAMED | 2,625 | 68 km |
| 2010 | FORT DIX RANGE 1-14 | 2,615 | 66 km |
| 1990 | UNNAMED | 2,367 | 47 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 34°F (1°C) | 3.5 in | Coldest |
| February | 34°F (1°C) | 2.8 in | Driest |
| March | 43°F (6°C) | 3.9 in | |
| April | 52°F (11°C) | 3.7 in | |
| May | 63°F (17°C) | 4.1 in | |
| June | 72°F (22°C) | 3.6 in | |
| July | 79°F (26°C) | 4.5 in | Warmest, Wettest |
| August | 75°F (24°C) | 4.2 in | |
| September | 68°F (20°C) | 3.9 in | |
| October | 57°F (14°C) | 3.0 in | |
| November | 47°F (8°C) | 3.5 in | |
| December | 37°F (3°C) | 3.5 in |
Aldan has a seasonal temperature swing of 45°F / from 34°F in January to 79°F in July. Total annual precipitation is 44.2 inches, with July being the wettest month (4.5") and February the driest (2.8").