San Anselmo, CA
Full City Profile · California · San Mateo County County
3.7
/5.0
B+
Good
12,711
Population
4,743/sq mi density
$170,457
Median Income
$98,602 per capita
$1,524,300
Home Value
$1,665,524 Zillow
$2,750
Median Rent
33.8% income on rent
60°F
Avg Temperature
B+
Overall
3.7 / 5.0
Good overall score based on economy, affordability, safety and education
A+
Economy
4.5 / 5.0
$170,457 median income, 5.4% unemployment
D
Affordability
1.6 / 5.0
$1,524,300 home value, $2,750/mo rent
A+
Education
5.0 / 5.0
70.8% bachelor's degree or higher
San Anselmo enjoys a temperate climate with an average annual temperature of 60°F (16°C). Winters average 50°F in January while summers reach 68°F in July. Annual precipitation totals 34.5 inches. The area receives 0.0 inches of snow annually. Air quality is rated Good with a median AQI of 27.
Temperature
50°F Jan (10°C)
68°F Jul (20°C)
| Annual Average | 59.5°F |
| 10% above US avg | |
| January Average | 50°F (10°C) |
| July Average | 68°F (20°C) |
Geography
| Elevation | 83 ft (25 m) |
| Area | 2.7 sq mi (6.9 km²) |
| Population Density | 4,743/sq mi |
| Coordinates | 37.9821°N, 122.5699°W |
| Timezone | America/Los_Angeles |
| County | San Mateo County County |
| Nearest Airport | Metro Oakland International (OAK) 26 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 | 52 km |
| 1989 | N. CALIFORNIA | Earthquake | 1.0 m | 62 | 121 km |
| 1856 | N. CALIFORNIA | Eruption + Earthquake | 0.6 m | - | 59 km |
| 1906 | N. CALIFORNIA | Eruption + Earthquake | 0.1 m | - | 32 km |
| 1865 | N. CALIFORNIA | Eruption + Earthquake | - | - | 105 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Nearby Volcanoes
1 volcano within 200 km. Closest: Clear Lake (111 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Clear Lake | Volcanic field | 1,439 m (4,721 ft) | Unknown | 111 km |
Source: Smithsonian Institution Global Volcanism Program (GVP). Sorted by distance.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 50°F (10°C) | 7.1 in | |
| February | 53°F (11°C) | 6.9 in | |
| March | 55°F (13°C) | 4.4 in | |
| April | 58°F (14°C) | 2.0 in | |
| May | 61°F (16°C) | 0.9 in | |
| June | 66°F (19°C) | 0.2 in | |
| July | 68°F (20°C) | 0.0 in | Driest |
| August | 68°F (20°C) | 0.1 in | Warmest |
| September | 68°F (20°C) | 0.1 in | |
| October | 63°F (17°C) | 1.5 in | |
| November | 55°F (13°C) | 3.5 in | |
| December | 50°F (10°C) | 7.8 in | Coldest, Wettest |
San Anselmo has a seasonal temperature swing of 19°F / from 50°F in December to 68°F in August. Total annual precipitation is 34.5 inches, with December being the wettest month (7.8") and July the driest (0.0").