Local weather forecast

Weather in Castro Valley, CA

Updated 2026-08-11 10:00 local time · ZIP codes 94546, 94552

Partly cloudy
Now62°F

Partly cloudy

High / Low80° / 55°
Rain chance12%
Wind3 mph
Weather alerts

Active alerts

1
Coastal Flood Advisory issued August 10 at 10:18PM PDT until August 13 at 2:00AM PDT by NWS San Francisco CA

* WHAT...Up to 1.6 ft of inundation above ground level is possible in low-lying areas near shorelines and tidal waterways. * WHERE...Bayshore locations along the San Francisco Bay, San Pablo Bay, and Monterey Bay. * WHEN...Until 2 AM PDT Thursday. * IMPACTS...Flooding of lots, parks, and roads with only isolated road closures expected. * ADDITIONAL DETAILS...At the San Francisco tidal gauge, high tide is expected to be 1.6 ft above normal (7.44 ft MLLW) at 10:57 PM Tuesday 8/11 and 1.4 ft above normal (7.24 ft MLLW) at 11:49 PM Wednesday 8/12. These predictions include both astronomical tides and roughly 3-6 inches of additional water mainly from a combination of thermal expansion and accumulated sea level rise since the tidal datum was established (1983- 2001). High tide varies up to 90 minutes earlier or later along the Pacific Coast and through the San Francisco Bay, respectively.

Safety instructions

If travel is required, allow extra time as some roads may be closed. Do not drive around barricades or through water of unknown depth. Take the necessary actions to protect flood-prone property.

Hourly

Next hours

NowPartly cloudy62°7% rain
11 AMSunny71°6% rain
12 PMSunny73°5% rain
1 PMSunny76°4% rain
2 PMSunny77°3% rain
3 PMSunny80°3% rain
4 PMSunny79°3% rain
5 PMSunny77°4% rain
6 PMSunny73°5% rain
7 PMSunny64°9% rain
8 PMSunny60°14% rain
9 PMPartly Cloudy59°16% rain
Forecast

3-day weather forecast

Today2026-08-11
Sunny
80° 55°Sunny
Rain 12%Gust 8 mph
Tomorrow2026-08-12
Sunny
82° 57°Sunny
Rain 5%Gust 9 mph
Thursday2026-08-13
Partly Cloudy
73° 57°Partly Cloudy
Rain 11%Gust 13 mph
Conditions

Weather details

Feels like62°F
Humidity77%
Pressure29.97 inHg
Visibility9 mi
Wind3 mph SW
Wind gusts4 mph
Precipitation0.00 in
UV index4
Daylight

Sunrise, sunset and moon

Sunrise06:20 AM
Sunset08:06 PM
Moonrise04:32 AM
Moon phaseNew Moon
Practical guide

Weather insights for today

Umbrella not essential

Rain chance stays relatively low over the next 12 hours (up to 16%).

Light layers should work

It feels like 62°F with winds near 3 mph.

Best window: 11 AM

71°F, 6% rain chance and 4 mph wind.

Driving conditions look generally normal

Visibility is around 9 mi; gusts may reach 10 mph.

Good conditions for an easy run

Current temperature is 62°F, wind 3 mph, rain chance up to 16%.

Moderate UV protection recommended

UV index is 4. Sunscreen and sunglasses are sensible for longer outdoor time.

Castro Valley weather today

Partly cloudy and 62°F in Castro Valley, CA. Today's high is 80°F with a 12% rain chance. Winds are around 3 mph with gusts near 4 mph. Relative humidity is 77%, pressure is 29.97 inHg, and visibility is about 9 miles.

Tonight and tomorrow in Castro Valley

Sunrise is at 06:20 AM and sunset is at 08:06 PM. Tomorrow's forecast calls for Sunny with a high near 82°F and a low near 57°F. The maximum rain chance is 5%.

Nearby

Weather near Castro Valley

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