Live Weather & Forecast
Weather in Castro Valley
California, United States · Real-time conditions & 3-day outlook
11°C
Feels like 8°C
51°F / Feels 47°F
Patchy light rain
Castro Valley, California
🌙 Nighttime
Updated: 2026-04-11 21:45
Humidity
92%
Wind
16.9 km/h SW
Wind Gust
27 km/h
Pressure
1009 mb
Visibility
16 km
UV Index
0
(Low)
Precipitation
2.29 mm
Cloud Cover
25%
Dew Point
9.5°C
Wind Degree
218°
Air Quality Index
US EPA: Good
UK DEFRA: Low (1)
CO
151.9 μg/m³
NO₂
6.7 μg/m³
O₃
70 μg/m³
SO₂
2.5 μg/m³
PM 2.5
6.2 μg/m³
PM 10
8.3 μg/m³
Weather Alerts 1
Met
· Moderate · Expected
Special Weather Statement issued April 11 at 5:13PM PDT by NWS San Francisco CA
At 513 PM PDT, Doppler radar was tracking a line of strong thunderstorms extending from over South San Francisco to 28 miles south of Half Moon Bay, or extending from over South San Francisco to 34 miles southwest of San Carlos, moving northeast at 35 mph. HAZARD...Wind gusts of 50 to 55 mph. SOURCE...Radar indicated. IMPACT...Gusty winds could knock down tree limbs and blow around unsecured ob...
Monitor the weather situation closely and be alert for threatening weather conditions.
Today's Hourly Forecast
24-hour breakdown for Castro Valley, California
12 AM
14°
Patchy rain nearby
1 AM
14°
Light drizzle
2 AM
13°
Patchy rain nearby
3 AM
13°
Light drizzle
4 AM
13°
Patchy rain nearby
5 AM
13°
Cloudy
6 AM
13°
Patchy rain nearby
7 AM
13°
Overcast
8 AM
13°
Overcast
9 AM
14°
Cloudy
10 AM
14°
Cloudy
11 AM
14°
Patchy rain nearby
12 PM
14°
Light drizzle
1 PM
16°
Patchy rain nearby
2 PM
17°
Sunny
3 PM
17°
Sunny
4 PM
16°
Cloudy
5 PM
15°
Light drizzle
6 PM
13°
Light drizzle
7 PM
12°
Heavy rain
8 PM
11°
Moderate rain at times
9 PM
11°
Patchy light rain
10 PM
10°
Moderate rain at times
11 PM
10°
Clear
3-Day Forecast
Daily overview for Castro Valley, California
Today
Moderate rain
19°
/
10°
🌧️ 87% chance of rain
💧 Avg. humidity: 85%
💨 Max wind: 31 km/h
🌧️ Total precip: 18.59 mm
☀️ UV Index: 1.3
🌅 Sunrise: 06:39 AM
🌇 Sunset: 07:41 PM
🌙 Waning Crescent
🌑 Moon: 42% lit
Sun, Apr 12
Moderate rain
14°
/
8°
🌧️ 88% chance of rain
💧 Avg. humidity: 83%
💨 Max wind: 22.7 km/h
🌧️ Total precip: 9.08 mm
☀️ UV Index: 1.1
🌅 Sunrise: 06:37 AM
🌇 Sunset: 07:42 PM
🌙 Waning Crescent
🌑 Moon: 33% lit
Mon, Apr 13
Partly Cloudy
16°
/
9°
🌧️ 0% chance of rain
💧 Avg. humidity: 83%
💨 Max wind: 18 km/h
🌧️ Total precip: 0 mm
☀️ UV Index: 1.4
🌅 Sunrise: 06:36 AM
🌇 Sunset: 07:43 PM
🌙 Waning Crescent
🌑 Moon: 23% lit
Best Time to Visit Castro Valley
Plan your trip to Castro Valley, United States around the most favorable weather conditions.
Peak Season
June – September
Warm, dry summers — ideal for outdoor activities.
Shoulder Season
April – May, October
Fewer crowds, moderate prices, mild weather.
Off Season
November – March
Cooler temperatures; some regions may experience rain or snow.
Frequently Asked Questions
People also ask — answers optimized for search engines and voice queries.
What is the current weather in Castro Valley?
Current conditions in Castro Valley: Patchy light rain, temperature 11°C, humidity 92%.
What is the best time to visit Castro Valley?
The best time to visit Castro Valley is typically June – September. Warm, dry summers — ideal for outdoor activities.
What is the climate like in Castro Valley?
Castro Valley is located at approximately 37.7° latitude. It has a temperate climate with warm summers and cold winters.
Does it rain a lot in Castro Valley?
The wettest period in Castro Valley is typically during November – March. Cooler temperatures; some regions may experience rain or snow.
What should I pack for a trip to Castro Valley?
For visits to Castro Valley during June – September: light clothing and sun protection. For November – March: layers and a waterproof jacket are recommended.
What country is Castro Valley in?
Castro Valley is located in United States, in the state of California.
What are the public holidays in Castro Valley in 2026?
View the 2026 public holidays for Castro Valley on our Holidays page.
What are the GPS coordinates used for the weather forecast in Castro Valley?
The weather forecast for Castro Valley uses coordinates 37.7136, -122.0716.