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Weather & Climate in Mercerville, NJ
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Mercerville experiences four distinct seasons with an average annual temperature of 53°F (12°C). Winters average 31°F in January while summers reach 76°F in July. The area gets 275 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 47.4 inches (wetter than the 38-inch national average). Air quality is rated Good with a median AQI of 39. The city sits at an elevation of 86 feet.
Temperature
31°F Jan (-0°C)
76°F Jul (24°C)
| Annual Average | 53.4°F |
| 1% below US avg | |
| January Average | 31°F (-0°C) |
| July Average | 76°F (24°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 86 ft (26 m) |
| Area | 1.4 sq mi (3.7 km²) |
| Population Density | 3,711/sq mi |
| Coordinates | 40.2358°N, 74.6923°W |
| Timezone | America/New_York |
| County | Mercer County County |
| Nearest Airport | Central Jersey Regional (JVI) 21 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 39.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively High |
| Risk Score | 95.4 / 100 |
| Social Vulnerability | 46.9 / 100 |
| Community Resilience | 70.2 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | Relatively High |
| Earthquake | Relatively Moderate |
| Wildfire | Relatively Low |
| Flood | Relatively High |
| Hail | Very Low |
| Strong Wind | Very High |
| Heat Wave | Relatively Moderate |
| Winter Weather | Very High |
| Lightning | Relatively High |
| Ice Storm | Very High |
| Drought | Relatively Low |
| Cold Wave | Relatively Moderate |
| Landslide | Very Low |
| Coastal Flood | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
32 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.8.
| Apr 5, 2024 | 2024 Tewksbury, New Jersey Earthquake | M4.8 | 52 km | 3 km |
| Jan 16, 1994 | 2 km W of Sinking Spring, Pennsylvania | M4.6 | 115 km | 5 km |
| Jan 16, 1994 | 0 km E of Sinking Spring, Pennsylvania | M4.2 | 112 km | 5 km |
| Apr 5, 2024 | 7 km WSW of Gladstone, New Jersey | M3.7 | 51 km | 4 km |
| Oct 23, 1990 | 3 km W of Hancocks Bridge, New Jersey | M3.2 | 106 km | 10 km |
| Aug 26, 2003 | 4 km NNW of Milford, New Jersey | M3.1 | 54 km | 3 km |
| Jan 9, 1992 | 4 km WNW of Robertsville, New Jersey | M3.1 | 33 km | 8 km |
| Nov 14, 1997 | 0 km S of Rothsville, Pennsylvania | M3.0 | 133 km | 5 km |
| Aug 3, 2025 | 0 km W of Little Ferry, New Jersey | M3.0 | 88 km | 10 km |
| Oct 28, 1991 | 3 km WNW of Stamford, Connecticut | M3.0 | 132 km | 10 km |
| Feb 3, 2009 | 1 km ESE of Victory Gardens, New Jersey | M3.0 | 72 km | 0 km |
| Jan 16, 1994 | 0 km SSE of Sinking Spring, Pennsylvania | M2.9 | 112 km | 5 km |
| May 24, 2024 | 6 km E of Califon, New Jersey | M2.9 | 53 km | 7 km |
| Apr 27, 2024 | 7 km WSW of Gladstone, New Jersey | M2.9 | 51 km | 5 km |
| May 10, 1993 | 1 km NW of Whitfield, Pennsylvania | M2.8 | 113 km | 5 km |
| Aug 5, 2025 | 1 km N of Hillsdale, New Jersey | M2.8 | 103 km | 12 km |
| Jul 1, 2009 | 3 km ESE of Pennsville, New Jersey | M2.8 | 94 km | 5 km |
| Apr 12, 1991 | 2 km ENE of North Castle, New York | M2.7 | 134 km | 9 km |
| Mar 11, 1995 | 0 km ENE of Landisville, Pennsylvania | M2.7 | 146 km | 5 km |
| Jan 25, 2015 | 4 km ESE of Downingtown, Pennsylvania | M2.6 | 86 km | 2 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 |
| 2014 | Arthur | Category 1 | 81 mph | 284 km |
| 2012 | Sandy | Category 2 | 92 mph | 251 km |
| 2011 | Irene | Category 1 | 75 mph | 239 km |
| 1991 | Bob | Category 3 | 109 mph | 208 km |
| 1985 | Gloria | Category 2 | 98 mph | 97 km |
Source: NOAA IBTrACS (Category 1+, 1980–2026).
Tornado History
306 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 8 fatalities, 209 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Sep 1, 2021 | EF3 | 78 km | 12.4 mi | 0 |
| Jul 29, 2021 | EF3 | 29 km | 3.4 mi | 0 |
| Jul 27, 1994 | EF3 | 70 km | 2.0 mi | 3 |
| Oct 18, 1990 | EF3 | 28 km | 0.5 mi | 0 |
| Jul 21, 1983 | EF3 | 72 km | 0.2 mi | 0 |
| Jul 26, 1981 | EF3 | 96 km | 3.3 mi | 0 |
| Sep 26, 1977 | EF3 | 21 km | 5.9 mi | 0 |
| Mar 21, 1976 | EF3 | 92 km | 0.5 mi | 0 |
| May 28, 1973 | EF3 | 65 km | 0.4 mi | 0 |
| May 28, 1973 | EF3 | 68 km | 0.4 mi | 0 |
| Apr 28, 1961 | EF3 | 98 km | 0.3 mi | 0 |
| Jun 24, 1960 | EF3 | 8 km | 12.9 mi | 0 |
| Mar 22, 1955 | EF3 | 84 km | 9.6 mi | 1 |
| Apr 1, 2023 | EF2 | 57 km | 0.1 mi | 0 |
| Apr 1, 2023 | EF2 | 37 km | 1.6 mi | 0 |
| Apr 1, 2023 | EF2 | 27 km | 2.1 mi | 0 |
| Feb 21, 2023 | EF2 | 5 km | 5.8 mi | 0 |
| Sep 1, 2021 | EF2 | 49 km | 8.3 mi | 1 |
| Jul 29, 2021 | EF2 | 25 km | 6.3 mi | 0 |
| Jul 29, 2021 | EF2 | 69 km | 4.2 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Tsunami History
3 tsunamis recorded within 500 km. Highest wave on record: 0.3 m (1 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1964 | LONG ISLAND, NY | Meteorological | 0.3 m | — | 149 km |
| 1895 | HIGH BRIDGE, NJ | Earthquake | — | — | 51 km |
| 1840 | PHILADELPHIA, PENNSYLVANIA | Earthquake | — | — | 65 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 | 57 km |
| 2007 | WARREN GROVE | 15,315 | 67 km |
| 2022 | MULLICA RIVER FIRE | 13,082 | 61 km |
| 1999 | BASS RIVER | 12,129 | 67 km |
| 2019 | SPRING HILL FIRE | 8,182 | 54 km |
| 2023 | ALLEN ROAD | 6,213 | 68 km |
| 1992 | FORKED RIVER MOUTAIN APR | 5,093 | 54 km |
| 1992 | POWER PLANT | 4,928 | 59 km |
| 1992 | UNNAMED | 4,470 | 31 km |
| 2024 | TEA TIME HILL | 4,444 | 50 km |
| 2006 | UNNAMED | 3,780 | 58 km |
| 2017 | PENN SWAMP FIRE | 3,587 | 62 km |
| 2023 | JIMMYS WATER HOLE | 3,585 | 37 km |
| 1989 | SIMM PLACE | 3,262 | 55 km |
| 2002 | UNNAMED | 2,824 | 30 km |
| 2007 | ATSION | 2,705 | 57 km |
| 1992 | FOUR MILE COLONY | 2,647 | 43 km |
| 1996 | UNNAMED | 2,625 | 64 km |
| 2010 | FORT DIX RANGE 1-14 | 2,615 | 28 km |
| 1990 | UNNAMED | 2,367 | 52 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 31°F (-0°C) | 3.7 in | Coldest |
| February | 33°F (1°C) | 2.9 in | Driest |
| March | 41°F (5°C) | 4.0 in | |
| April | 51°F (11°C) | 3.9 in | |
| May | 62°F (16°C) | 4.4 in | |
| June | 70°F (21°C) | 3.9 in | |
| July | 76°F (24°C) | 4.8 in | Warmest, Wettest |
| August | 74°F (23°C) | 4.5 in | |
| September | 67°F (19°C) | 4.1 in | |
| October | 55°F (13°C) | 3.5 in | |
| November | 46°F (8°C) | 3.8 in | |
| December | 36°F (2°C) | 3.7 in |
Mercerville has a seasonal temperature swing of 45°F / from 31°F in January to 76°F in July. Total annual precipitation is 47.1 inches, with July being the wettest month (4.8") and February the driest (2.9").