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Rocky Hill, NJ
Full City Profile · New Jersey · Mercer County County
3.7
/5.0
B+
Good
814
Population
1,334/sq mi density
$127,344
Median Income
$77,165 per capita
$608,200
Home Value
$727,931 Zillow
$1,660
Median Rent
21.1% income on rent
53°F
Avg Temperature
271 sunny days/yr
69
Violent Crime/100K
926 property/100K
B+
Overall
3.7 / 5.0
Good overall score based on economy, affordability, safety and education
A+
Economy
4.7 / 5.0
$127,344 median income, 4.2% unemployment
B+
Affordability
4.0 / 5.0
$608,200 home value, $1,660/mo rent
F
Safety
1.0 / 5.0
69 violent crimes/100K
A+
Education
5.0 / 5.0
72.4% bachelor's degree or higher
Rocky Hill experiences four distinct seasons with an average annual temperature of 53°F (12°C). Winters average 30°F in January while summers reach 75°F in July. The area gets 271 sunny days per year. Annual precipitation totals 51.0 inches. The area receives 23.9 inches of snow annually. Air quality is rated Good with a median AQI of 39.
Temperature
30°F Jan (-1°C)
75°F Jul (24°C)
| Annual Average | 52.5°F |
| 3% below US avg | |
| January Average | 30°F (-1°C) |
| July Average | 75°F (24°C) |
| Sunny Days | 271 days/yr |
Geography
| Elevation | 93 ft (28 m) |
| Area | 0.6 sq mi (1.6 km²) |
| Population Density | 1,334/sq mi |
| Coordinates | 40.4003°N, 74.6389°W |
| Timezone | America/New_York |
| County | Mercer County County |
| Nearest Airport | Central Jersey Regional (JVI) 9 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 39.0 |
| Rating | Good |
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 | — | 137 km |
| 1895 | HIGH BRIDGE, NJ | Earthquake | — | — | 36 km |
| 1840 | PHILADELPHIA, PENNSYLVANIA | Earthquake | — | — | 82 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 30°F (-1°C) | 3.8 in | Coldest |
| February | 32°F (-0°C) | 3.0 in | Driest |
| March | 41°F (5°C) | 4.0 in | |
| April | 50°F (10°C) | 4.1 in | |
| May | 60°F (16°C) | 4.5 in | |
| June | 69°F (21°C) | 4.0 in | |
| July | 75°F (24°C) | 5.0 in | Warmest, Wettest |
| August | 73°F (23°C) | 4.5 in | |
| September | 66°F (19°C) | 4.3 in | |
| October | 54°F (12°C) | 3.5 in | |
| November | 45°F (7°C) | 3.9 in | |
| December | 35°F (2°C) | 3.8 in |
Rocky Hill has a seasonal temperature swing of 45°F / from 30°F in January to 75°F in July. Total annual precipitation is 48.3 inches, with July being the wettest month (5.0") and February the driest (3.0").