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Foster City, CA
Full City Profile · California · San Mateo County County
3.1
/5.0
B
Good
32,964
Population
8,698/sq mi density
$193,633
Median Income
$95,509 per capita
$1,774,500
Home Value
$1,861,130 Zillow
$3,501
Median Rent
25.7% income on rent
59°F
Avg Temperature
330 sunny days/yr
113
Violent Crime/100K
1,227 property/100K
B
Overall
3.1 / 5.0
Good overall score based on economy, affordability, safety and education
A+
Economy
4.8 / 5.0
$193,633 median income, 3.2% unemployment
F
Affordability
1.5 / 5.0
$1,774,500 home value, $3,501/mo rent
F
Safety
1.0 / 5.0
113 violent crimes/100K
A+
Education
5.0 / 5.0
74.1% bachelor's degree or higher
Foster City enjoys a temperate climate with an average annual temperature of 59°F (15°C). Winters average 51°F in January while summers reach 64°F in July. The area gets 330 sunny days per year. Annual precipitation totals 19.6 inches. Air quality is rated Good with a median AQI of 48.
Temperature
51°F Jan (11°C)
64°F Jul (18°C)
| Annual Average | 58.7°F |
| 9% above US avg | |
| January Average | 51°F (11°C) |
| July Average | 64°F (18°C) |
| Sunny Days | 330 days/yr |
Geography
| Elevation | 7 ft (2 m) |
| Area | 19.8 sq mi (51.4 km²) |
| Population Density | 8,698/sq mi |
| Coordinates | 37.5648°N, 122.2508°W |
| Timezone | America/Los_Angeles |
| County | San Mateo County County |
| Nearest Airport | San Francisco International (SFO) 8 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 48.0 |
| Rating | Good |
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 | 20 km |
| 1989 | N. CALIFORNIA | Earthquake | 1.0 m | 62 | 67 km |
| 1856 | N. CALIFORNIA | Eruption + Earthquake | 0.6 m | — | 8 km |
| 1906 | N. CALIFORNIA | Eruption + Earthquake | 0.1 m | — | 27 km |
| 1865 | N. CALIFORNIA | Eruption + Earthquake | — | — | 51 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Nearby Volcanoes
1 volcano within 200 km. Closest: Clear Lake (163 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Clear Lake | Volcanic field | 1,439 m (4,721 ft) | Unknown | 163 km |
Source: Smithsonian Institution Global Volcanism Program (GVP). Sorted by distance.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 51°F (11°C) | 4.1 in | Wettest |
| February | 53°F (11°C) | 3.5 in | |
| March | 54°F (12°C) | 3.1 in | |
| April | 57°F (14°C) | 1.3 in | |
| May | 60°F (15°C) | 0.4 in | |
| June | 63°F (17°C) | 0.1 in | |
| July | 64°F (18°C) | 0.0 in | Driest |
| August | 66°F (19°C) | 0.1 in | Warmest |
| September | 65°F (18°C) | 0.2 in | |
| October | 61°F (16°C) | 1.2 in | |
| November | 55°F (13°C) | 2.9 in | |
| December | 49°F (10°C) | 3.0 in | Coldest |
Foster City has a seasonal temperature swing of 16°F / from 49°F in December to 66°F in August. Total annual precipitation is 19.8 inches, with January being the wettest month (4.1") and July the driest (0.0").