Millbrae, CA
Full City Profile · California · San Mateo County County
3.5
/5.0
B+
Good
22,589
Population
6,908/sq mi density
$157,567
Median Income
$76,277 per capita
$1,929,700
Home Value
$2,047,946 Zillow
$3,401
Median Rent
31.1% income on rent
59°F
Avg Temperature
B+
Overall
3.5 / 5.0
Good overall score based on economy, affordability, safety and education
A
Economy
4.4 / 5.0
$157,567 median income, 6.3% unemployment
F
Affordability
1.0 / 5.0
$1,929,700 home value, $3,401/mo rent
A+
Education
5.0 / 5.0
50.5% bachelor's degree or higher
Millbrae 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. Annual precipitation totals 19.6 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)
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) |
Geography
| Elevation | 99 ft (30 m) |
| Area | 3.3 sq mi (8.4 km²) |
| Population Density | 6,908/sq mi |
| Coordinates | 37.5990°N, 122.4020°W |
| Timezone | America/Los_Angeles |
| County | San Mateo County County |
| Nearest Airport | San Francisco International (SFO) 2 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 | 29 km |
| 1989 | N. CALIFORNIA | Earthquake | 1.0 m | 62 | 78 km |
| 1856 | N. CALIFORNIA | Eruption + Earthquake | 0.6 m | - | 14 km |
| 1906 | N. CALIFORNIA | Eruption + Earthquake | 0.1 m | - | 14 km |
| 1865 | N. CALIFORNIA | Eruption + Earthquake | - | - | 63 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Nearby Volcanoes
1 volcano within 200 km. Closest: Clear Lake (156 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Clear Lake | Volcanic field | 1,439 m (4,721 ft) | Unknown | 156 km |
Source: Smithsonian Institution Global Volcanism Program (GVP). Sorted by distance.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 51°F (11°C) | 3.9 in | Coldest |
| February | 54°F (12°C) | 4.0 in | |
| March | 56°F (13°C) | 2.7 in | |
| April | 57°F (14°C) | 1.4 in | |
| May | 60°F (16°C) | 0.5 in | |
| June | 63°F (17°C) | 0.1 in | |
| July | 64°F (18°C) | 0.0 in | Driest |
| August | 65°F (18°C) | 0.0 in | |
| September | 65°F (19°C) | 0.1 in | Warmest |
| October | 63°F (17°C) | 0.8 in | |
| November | 56°F (14°C) | 2.0 in | |
| December | 51°F (11°C) | 4.1 in | Wettest |
Millbrae has a seasonal temperature swing of 14°F / from 51°F in January to 65°F in September. Total annual precipitation is 19.6 inches, with December being the wettest month (4.1") and July the driest (0.0").