Half Moon Bay, CA
Full City Profile · California · San Mateo County County
3.7
/5.0
B+
Good
11,454
Population
1,836/sq mi density
$153,199
Median Income
$81,034 per capita
$1,467,000
Home Value
$1,535,358 Zillow
$2,299
Median Rent
27.6% income on rent
55°F
Avg Temperature
B+
Overall
3.7 / 5.0
Good overall score based on economy, affordability, safety and education
A+
Economy
4.9 / 5.0
$153,199 median income, 2.5% unemployment
F
Affordability
1.2 / 5.0
$1,467,000 home value, $2,299/mo rent
A+
Education
5.0 / 5.0
53.2% bachelor's degree or higher
Half Moon Bay experiences four distinct seasons with an average annual temperature of 55°F (13°C). Winters average 51°F in January while summers reach 59°F in July. Annual precipitation totals 26.0 inches. The area receives 0.0 inches of snow annually. Air quality is rated Good with a median AQI of 27.
Temperature
51°F Jan (11°C)
59°F Jul (15°C)
| Annual Average | 54.9°F |
| 2% above US avg | |
| January Average | 51°F (11°C) |
| July Average | 59°F (15°C) |
Geography
| Elevation | 39 ft (12 m) |
| Area | 6.4 sq mi (16.7 km²) |
| Population Density | 1,836/sq mi |
| Coordinates | 37.4673°N, 122.4405°W |
| Timezone | America/Los_Angeles |
| County | San Mateo County County |
| Nearest Airport | San Francisco International (SFO) 11 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 27.0 |
| Rating | Good |
| Good Days % | 88.1% |
| Unhealthy Days | 0 |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0332 ppm |
| NO₂ (Nitrogen Dioxide) | 12.1 ppb |
| CO (Carbon Monoxide) | 0.34 ppm |
| PM2.5 (Fine Particles) | 4.5 μg/m³ |
Natural Hazard Risk
| Overall Risk | Relatively High |
| Risk Score | 99.2 / 100 |
| Social Vulnerability | 20.5 / 100 |
| Community Resilience | 97.6 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Earthquake | Relatively High |
| Wildfire | Relatively Moderate |
| Flood | Relatively High |
| Hail | Very Low |
| Strong Wind | Relatively Low |
| Heat Wave | Relatively Moderate |
| Winter Weather | Very Low |
| Lightning | Relatively Moderate |
| Drought | Relatively High |
| Cold Wave | No Rating |
| Landslide | Relatively High |
| Coastal Flood | Relatively High |
| Tsunami | Relatively Moderate |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Tsunami History
5 tsunamis recorded within 500 km. Highest wave on record: 4.5 m (15 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1868 | N. CALIFORNIA | Eruption + Earthquake | 4.5 m | 30 | 40 km |
| 1989 | N. CALIFORNIA | Earthquake | 1.0 m | 62 | 69 km |
| 1856 | N. CALIFORNIA | Eruption + Earthquake | 0.6 m | - | 13 km |
| 1906 | N. CALIFORNIA | Eruption + Earthquake | 0.1 m | - | 26 km |
| 1865 | N. CALIFORNIA | Eruption + Earthquake | - | - | 56 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Nearby Volcanoes
1 volcano within 200 km. Closest: Clear Lake (170 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Clear Lake | Volcanic field | 1,439 m (4,721 ft) | Unknown | 170 km |
Source: Smithsonian Institution Global Volcanism Program (GVP). Sorted by distance.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 51°F (11°C) | 5.1 in | |
| February | 51°F (11°C) | 4.7 in | |
| March | 52°F (11°C) | 3.7 in | |
| April | 53°F (12°C) | 1.8 in | |
| May | 55°F (13°C) | 1.0 in | |
| June | 57°F (14°C) | 0.4 in | |
| July | 59°F (15°C) | 0.1 in | Driest |
| August | 60°F (15°C) | 0.2 in | Warmest |
| September | 59°F (15°C) | 0.2 in | |
| October | 57°F (14°C) | 1.3 in | |
| November | 54°F (12°C) | 2.4 in | |
| December | 51°F (11°C) | 5.2 in | Coldest, Wettest |
Half Moon Bay has a seasonal temperature swing of 9°F / from 51°F in December to 60°F in August. Total annual precipitation is 26.0 inches, with December being the wettest month (5.2") and July the driest (0.1").