All Countries
Mendham, NJ
Full City Profile · New Jersey · Morris County County
4.3
/5.0
A
Great
4,977
Population
839/sq mi density
$223,750
Median Income
$114,107 per capita
$764,000
Home Value
$979,321 Zillow
$3,250
Median Rent
27.6% income on rent
53°F
Avg Temperature
275 sunny days/yr
A
Overall
4.3 / 5.0
Strong
A+
Economy
5.0 / 5.0
$223,750 median income, 2.1% unemployment
A+
Affordability
4.8 / 5.0
$764,000 home value, $3,250/mo rent
C+
Safety
2.5 / 5.0
0 violent crimes/100K
A+
Education
5.0 / 5.0
79.2% bachelor's degree or higher
Mendham 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 275 sunny days per year. Annual precipitation totals 45.5 inches. 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 | 275 days/yr |
Geography
| Elevation | 519 ft (158 m) |
| Area | 6.0 sq mi (15.5 km²) |
| Population Density | 839/sq mi |
| Coordinates | 40.7673°N, 74.5978°W |
| Timezone | America/New_York |
| County | Morris County County |
| Nearest Airport | Central Jersey Regional (JVI) 17 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 39.0 |
| Rating | Good |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0448 ppm |
| NO₂ (Nitrogen Dioxide) | 5.1 ppb |
| SO₂ (Sulfur Dioxide) | 0.82 ppb |
| PM2.5 (Fine Particles) | 6.7 μg/m³ |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 92.9 / 100 |
| Social Vulnerability | 10.6 / 100 |
| Community Resilience | 89.5 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | Relatively Moderate |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively High |
| Hail | Very Low |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Moderate |
| Winter Weather | Very High |
| Lightning | Relatively High |
| Ice Storm | Relatively Low |
| Drought | Relatively Moderate |
| Cold Wave | Relatively High |
| Landslide | Relatively Low |
| Avalanche | Very 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 | — | 126 km |
| 1895 | HIGH BRIDGE, NJ | Earthquake | — | — | 27 km |
| 1840 | PHILADELPHIA, PENNSYLVANIA | Earthquake | — | — | 119 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 30°F (-1°C) | 3.9 in | |
| February | 30°F (-1°C) | 3.2 in | Coldest, Driest |
| March | 38°F (3°C) | 4.1 in | |
| April | 48°F (9°C) | 4.3 in | |
| May | 59°F (15°C) | 4.8 in | |
| June | 67°F (19°C) | 4.3 in | |
| July | 75°F (24°C) | 5.0 in | Warmest, Wettest |
| August | 71°F (21°C) | 4.5 in | |
| September | 64°F (18°C) | 4.6 in | |
| October | 52°F (11°C) | 3.9 in | |
| November | 43°F (6°C) | 4.3 in | |
| December | 33°F (0°C) | 3.9 in |
Mendham has a seasonal temperature swing of 45°F / from 30°F in February to 75°F in July. Total annual precipitation is 50.8 inches, with July being the wettest month (5.0") and February the driest (3.2").