East Rocky Hill, NJ
Full City Profile · New Jersey · Mercer County County
4.6
/5.0
A+
Excellent
212
Population
51/sq mi density
$232,727
Median Income
$137,482 per capita
$643,500
Home Value
$727,931 Zillow
52°F
Avg Temperature
A+
Overall
4.6 / 5.0
Strong
B+
Economy
3.8 / 5.0
$232,727 median income, 13.4% unemployment
A+
Affordability
5.0 / 5.0
$643,500 home value, /mo rent
A+
Education
5.0 / 5.0
64.9% bachelor's degree or higher
East Rocky Hill experiences four distinct seasons with an average annual temperature of 52°F (11°C). Winters average 30°F in January while summers reach 75°F in July. Annual precipitation totals 49.3 inches. The area receives 23.9 inches of snow annually. Air quality is rated Good with a median AQI of 43.
Temperature
30°F Jan (-1°C)
75°F Jul (24°C)
| Annual Average | 52.4°F |
| 3% below US avg | |
| January Average | 30°F (-1°C) |
| July Average | 75°F (24°C) |
Geography
| Elevation | 135 ft (41 m) |
| Area | 4.2 sq mi (10.8 km²) |
| Population Density | 51/sq mi |
| Coordinates | 40.4152°N, 74.6180°W |
| Timezone | America/New_York |
| County | Mercer County County |
| Nearest Airport | Central Jersey Regional (JVI) 8 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
| Good Days % | 67.2% |
| Unhealthy Days | 5 |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0450 ppm |
| PM2.5 (Fine Particles) | 9.6 μg/m³ |
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)
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 | - | 135 km |
| 1895 | HIGH BRIDGE, NJ | Earthquake | - | - | 36 km |
| 1840 | PHILADELPHIA, PENNSYLVANIA | Earthquake | - | - | 84 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 30°F (-1°C) | 2.9 in | Coldest |
| February | 32°F (-0°C) | 2.9 in | Driest |
| March | 40°F (4°C) | 4.5 in | |
| April | 51°F (11°C) | 4.3 in | |
| May | 61°F (16°C) | 3.9 in | |
| June | 70°F (21°C) | 4.8 in | |
| July | 75°F (24°C) | 5.1 in | Warmest, Wettest |
| August | 73°F (23°C) | 4.5 in | |
| September | 66°F (19°C) | 4.2 in | |
| October | 54°F (12°C) | 4.3 in | |
| November | 44°F (7°C) | 3.4 in | |
| December | 35°F (2°C) | 4.5 in |
East Rocky Hill has a seasonal temperature swing of 45°F / from 30°F in January to 75°F in July. Total annual precipitation is 49.3 inches, with July being the wettest month (5.1") and February the driest (2.9").