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Diablo, CA
Full City Profile · California · Contra Costa County County
3.0
/5.0
B
Good
1,072
Population
788/sq mi density
$2,000,001
Home Value
$3,072,481 Zillow
58°F
Avg Temperature
323 sunny days/yr
39
Violent Crime/100K
1,005 property/100K
B
Overall
3.0 / 5.0
Good overall score based on economy, affordability, safety and education
F
Safety
1.0 / 5.0
39 violent crimes/100K
A+
Education
5.0 / 5.0
84.1% bachelor's degree or higher
Diablo enjoys a temperate climate with an average annual temperature of 58°F (14°C). Winters average 48°F in January while summers reach 72°F in July. The area gets 323 sunny days per year. Annual precipitation totals 26.1 inches. The area receives 0.7 inches of snow annually. Air quality is rated Good with a median AQI of 48.
Temperature
48°F Jan (9°C)
72°F Jul (22°C)
| Annual Average | 58.4°F |
| 8% above US avg | |
| January Average | 48°F (9°C) |
| July Average | 72°F (22°C) |
| Sunny Days | 323 days/yr |
Geography
| Elevation | 661 ft (201 m) |
| Area | 1.4 sq mi (3.5 km²) |
| Population Density | 788/sq mi |
| Coordinates | 37.8408°N, 121.9565°W |
| Timezone | America/Los_Angeles |
| County | Contra Costa County County |
| Nearest Airport | Metro Oakland International (OAK) 17 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 48.0 |
| Rating | Good |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0361 ppm |
| NO₂ (Nitrogen Dioxide) | 7.4 ppb |
| SO₂ (Sulfur Dioxide) | 1.19 ppb |
| CO (Carbon Monoxide) | 0.29 ppm |
| PM2.5 (Fine Particles) | 7.6 μg/m³ |
Natural Hazard Risk
| Overall Risk | Very High |
| Risk Score | 99.5 / 100 |
| Social Vulnerability | 21.5 / 100 |
| Community Resilience | 67.8 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Earthquake | Relatively High |
| Wildfire | Relatively Moderate |
| Flood | Very High |
| Hail | Very Low |
| Strong Wind | Relatively Low |
| Heat Wave | Relatively High |
| Winter Weather | Very Low |
| Lightning | Relatively High |
| Drought | Relatively High |
| Cold Wave | No Rating |
| Landslide | Relatively High |
| Coastal Flood | Relatively Moderate |
| Tsunami | Relatively Low |
| Volcano | Very Low |
| Avalanche | Very Low |
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 | 90 km |
| 1856 | N. CALIFORNIA | Eruption + Earthquake | 0.6 m | — | 49 km |
| 1906 | N. CALIFORNIA | Eruption + Earthquake | 0.1 m | — | 50 km |
| 1865 | N. CALIFORNIA | Eruption + Earthquake | — | — | 71 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Nearby Volcanoes
1 volcano within 200 km. Closest: Clear Lake (144 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Clear Lake | Volcanic field | 1,439 m (4,721 ft) | Unknown | 144 km |
Source: Smithsonian Institution Global Volcanism Program (GVP). Sorted by distance.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 48°F (9°C) | 4.9 in | Wettest |
| February | 50°F (10°C) | 4.0 in | |
| March | 52°F (11°C) | 3.4 in | |
| April | 56°F (14°C) | 1.4 in | |
| May | 62°F (16°C) | 0.5 in | |
| June | 67°F (20°C) | 0.2 in | |
| July | 72°F (22°C) | 0.0 in | Driest |
| August | 72°F (22°C) | 0.1 in | Warmest |
| September | 70°F (21°C) | 0.3 in | |
| October | 64°F (18°C) | 1.3 in | |
| November | 54°F (12°C) | 3.4 in | |
| December | 47°F (8°C) | 3.6 in | Coldest |
Diablo has a seasonal temperature swing of 25°F / from 47°F in December to 72°F in August. Total annual precipitation is 23.1 inches, with January being the wettest month (4.9") and July the driest (0.0").