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South San Francisco, CA
Full City Profile · California · San Mateo County County
3.0
/5.0
B
Good
64,487
Population
7,009/sq mi density
$135,909
Median Income
$61,431 per capita
$1,160,100
Home Value
$1,212,996 Zillow
$2,833
Median Rent
30.4% income on rent
59°F
Avg Temperature
330 sunny days/yr
243
Violent Crime/100K
2,174 property/100K
B
Overall
3.0 / 5.0
Good overall score based on economy, affordability, safety and education
A+
Economy
5.0 / 5.0
$135,909 median income, 1.7% unemployment
D
Affordability
1.8 / 5.0
$1,160,100 home value, $2,833/mo rent
F
Safety
1.0 / 5.0
243 violent crimes/100K
A
Education
4.2 / 5.0
40.1% bachelor's degree or higher
South San Francisco 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 | 10 ft (3 m) |
| Area | 30.2 sq mi (78.1 km²) |
| Population Density | 7,009/sq mi |
| Coordinates | 37.6551°N, 122.3762°W |
| Timezone | America/Los_Angeles |
| County | San Mateo County County |
| Nearest Airport | San Francisco International (SFO) 3 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 | 25 km |
| 1989 | N. CALIFORNIA | Earthquake | 1.0 m | 62 | 82 km |
| 1856 | N. CALIFORNIA | Eruption + Earthquake | 0.6 m | — | 19 km |
| 1906 | N. CALIFORNIA | Eruption + Earthquake | 0.1 m | — | 12 km |
| 1865 | N. CALIFORNIA | Eruption + Earthquake | — | — | 66 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Nearby Volcanoes
1 volcano within 200 km. Closest: Clear Lake (150 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Clear Lake | Volcanic field | 1,439 m (4,721 ft) | Unknown | 150 km |
Source: Smithsonian Institution Global Volcanism Program (GVP). Sorted by distance.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 51°F (11°C) | 5.9 in | Wettest |
| February | 52°F (11°C) | 4.9 in | |
| March | 53°F (11°C) | 4.5 in | |
| April | 55°F (13°C) | 1.9 in | |
| May | 57°F (14°C) | 0.6 in | |
| June | 59°F (15°C) | 0.2 in | |
| July | 64°F (18°C) | 0.1 in | Warmest, Driest |
| August | 62°F (17°C) | 0.1 in | |
| September | 63°F (17°C) | 0.4 in | |
| October | 60°F (16°C) | 1.7 in | |
| November | 54°F (12°C) | 4.1 in | |
| December | 50°F (10°C) | 4.6 in | Coldest |
South San Francisco has a seasonal temperature swing of 14°F / from 50°F in December to 64°F in July. Total annual precipitation is 28.9 inches, with January being the wettest month (5.9") and July the driest (0.1").