San Carlos, CA
Full City Profile · California · San Mateo County County
3.8
/5.0
B+
Good
29,797
Population
5,508/sq mi density
$233,333
Median Income
$126,389 per capita
$2,000,001
Home Value
$2,432,476 Zillow
$2,802
Median Rent
26.0% income on rent
59°F
Avg Temperature
B+
Overall
3.8 / 5.0
Good overall score based on economy, affordability, safety and education
A+
Economy
4.6 / 5.0
$233,333 median income, 4.6% unemployment
D
Affordability
1.8 / 5.0
$2,000,001 home value, $2,802/mo rent
A+
Education
5.0 / 5.0
68.1% bachelor's degree or higher
San Carlos enjoys a temperate climate with an average annual temperature of 59°F (15°C). Winters average 50°F in January while summers reach 69°F in July. Annual precipitation totals 19.0 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)
69°F Jul (20°C)
| Annual Average | 59.4°F |
| 10% above US avg | |
| January Average | 50°F (10°C) |
| July Average | 69°F (20°C) |
Geography
| Elevation | 100 ft (30 m) |
| Area | 5.5 sq mi (14.3 km²) |
| Population Density | 5,508/sq mi |
| Coordinates | 37.4990°N, 122.2676°W |
| Timezone | America/Los_Angeles |
| County | San Mateo County County |
| Nearest Airport | San Francisco International (SFO) 10 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 | 27 km |
| 1989 | N. CALIFORNIA | Earthquake | 1.0 m | 62 | 62 km |
| 1856 | N. CALIFORNIA | Eruption + Earthquake | 0.6 m | - | 3 km |
| 1906 | N. CALIFORNIA | Eruption + Earthquake | 0.1 m | - | 30 km |
| 1865 | N. CALIFORNIA | Eruption + Earthquake | - | - | 47 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Nearby Volcanoes
1 volcano within 200 km. Closest: Clear Lake (169 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Clear Lake | Volcanic field | 1,439 m (4,721 ft) | Unknown | 169 km |
Source: Smithsonian Institution Global Volcanism Program (GVP). Sorted by distance.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 50°F (10°C) | 3.8 in | |
| February | 52°F (11°C) | 3.7 in | |
| March | 55°F (13°C) | 3.0 in | |
| April | 58°F (14°C) | 1.2 in | |
| May | 62°F (16°C) | 0.5 in | |
| June | 66°F (19°C) | 0.2 in | |
| July | 69°F (20°C) | 0.0 in | Warmest, Driest |
| August | 69°F (20°C) | 0.0 in | |
| September | 67°F (19°C) | 0.1 in | |
| October | 62°F (17°C) | 0.9 in | |
| November | 54°F (12°C) | 1.9 in | |
| December | 49°F (10°C) | 3.9 in | Coldest, Wettest |
San Carlos has a seasonal temperature swing of 19°F / from 49°F in December to 69°F in July. Total annual precipitation is 19.0 inches, with December being the wettest month (3.9") and July the driest (0.0").