San Marcos, CA
Full City Profile · California · Orange County County
3.1
/5.0
B
Good
94,078
Population
3,829/sq mi density
$105,286
Median Income
$44,376 per capita
$792,400
Home Value
$958,381 Zillow
$2,191
Median Rent
36.0% income on rent
63°F
Avg Temperature
223
Violent Crime/100K
674 property/100K
B
Overall
3.1 / 5.0
Good overall score based on economy, affordability, safety and education
A+
Economy
4.5 / 5.0
$105,286 median income, 4.5% unemployment
C
Affordability
2.4 / 5.0
$792,400 home value, $2,191/mo rent
F
Safety
1.0 / 5.0
223 violent crimes/100K
A
Education
4.4 / 5.0
42.7% bachelor's degree or higher
San Marcos enjoys a temperate climate with an average annual temperature of 63°F (17°C). Winters average 56°F in January while summers reach 69°F in July. Annual precipitation totals 11.4 inches. The area receives 0.0 inches of snow annually. Air quality is rated Moderate with a median AQI of 54.
Temperature
56°F Jan (14°C)
69°F Jul (21°C)
| Annual Average | 62.5°F |
| 16% above US avg | |
| January Average | 56°F (14°C) |
| July Average | 69°F (21°C) |
Geography
| Elevation | 636 ft (194 m) |
| Area | 24.4 sq mi (63.2 km²) |
| Population Density | 3,829/sq mi |
| Coordinates | 33.1326°N, 117.1699°W |
| Timezone | America/Los_Angeles |
| County | Orange County County |
| Nearest Airport | San Diego International (SAN) 28 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 54.0 |
| Rating | Moderate |
| Good Days % | 32.5% |
| Unhealthy Days | 16 |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0440 ppm |
| NO₂ (Nitrogen Dioxide) | 18.4 ppb |
| CO (Carbon Monoxide) | 0.35 ppm |
| PM2.5 (Fine Particles) | 9.7 μg/m³ |
Natural Hazard Risk
| Overall Risk | Very High |
| Risk Score | 99.8 / 100 |
| Social Vulnerability | 24.9 / 100 |
| Community Resilience | 16.3 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | No Rating |
| Earthquake | Very High |
| Wildfire | Relatively High |
| Flood | Very High |
| Hail | Relatively Moderate |
| Strong Wind | Relatively Moderate |
| Heat Wave | Relatively High |
| Winter Weather | Very Low |
| Lightning | Relatively Moderate |
| Drought | Relatively Low |
| Cold Wave | No Rating |
| Landslide | Relatively High |
| Coastal Flood | Relatively High |
| Tsunami | Relatively Low |
| Avalanche | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Tsunami History
2 tsunamis recorded within 500 km. Highest wave on record: 1.2 m (4 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1862 | S. CALIFORNIA | Eruption + Earthquake | 1.2 m | - | 48 km |
| 1855 | S. CALIFORNIA | Eruption + Earthquake | - | - | 138 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Nearby Volcanoes
1 volcano within 200 km. Closest: Salton Buttes (145 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Salton Buttes | Lava dome(s) | -40 m (-131 ft) | 210 | 145 km |
Source: Smithsonian Institution Global Volcanism Program (GVP). Sorted by distance.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 56°F (14°C) | 2.5 in | |
| February | 56°F (14°C) | 2.6 in | Wettest |
| March | 58°F (14°C) | 1.6 in | |
| April | 60°F (15°C) | 0.9 in | |
| May | 63°F (17°C) | 0.3 in | |
| June | 65°F (18°C) | 0.1 in | |
| July | 69°F (21°C) | 0.1 in | |
| August | 71°F (21°C) | 0.0 in | Warmest, Driest |
| September | 70°F (21°C) | 0.1 in | |
| October | 66°F (19°C) | 0.5 in | |
| November | 61°F (16°C) | 1.0 in | |
| December | 56°F (13°C) | 1.7 in | Coldest |
San Marcos has a seasonal temperature swing of 15°F / from 56°F in December to 71°F in August. Total annual precipitation is 11.4 inches, with February being the wettest month (2.6") and August the driest (0.0").