National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hawaii and Guam Concerns; Record Warmth Spreads Eastward; Heavy Snow for Sierra-Nevada; Severe Weather for the Plains

A very active spring pattern with tropical concerns across the Pacific. Heavy rainfall will continue to impact Hawaii this weekend. Meanwhile we continue to monitor a developing typhoon that may affect Guam into early next week. For the Lower 48, heavy snow for mountains of California this weekend, increase threat for severe thunderstorms next week for the Plains and record warmth spreads east. Read More >

Current conditions at

Hayward, Hayward Air Terminal (KHWD)

Lat: 37.66083°NLon: 122.11833°WElev: 46.0ft.

Overcast

59°F

15°C

Humidity 86%
Wind Speed SSW 6 MPH
Barometer 29.86 in (1011.18 mb)
Dewpoint 55°F (13°C)
Visibility 10.00 mi
Last update 10 Apr 09:26 PM PDT
Extended Forecast for

Castro Valley CA

  • Tonight

    Tonight: Rain and thunderstorms likely before 2am, then a slight chance of rain between 2am and 5am. Mostly cloudy, with a low around 54. South southwest wind around 7 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 54 °F

    Showers
    Likely then
    Chance Rain

  • Saturday

    Saturday: Rain and thunderstorms likely before 3pm, then a chance of showers and thunderstorms between 3pm and 4pm, then showers and possibly a thunderstorm after 4pm. High near 64. South wind 7 to 17 mph, with gusts as high as 28 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    High: 64 °F

    Showers

  • Saturday Night

    Saturday Night: Showers and possibly a thunderstorm. Low around 49. South southwest wind 10 to 16 mph, with gusts as high as 28 mph. Chance of precipitation is 100%. New rainfall amounts between a half and three quarters of an inch possible.

    Low: 49 °F

    Showers

  • Sunday

    Sunday: Showers and possibly a thunderstorm. High near 61. Southwest wind 10 to 13 mph, with gusts as high as 22 mph. Chance of precipitation is 90%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    High: 61 °F

    Showers

  • Sunday Night

    Sunday Night: A 40 percent chance of rain, mainly before 11pm. Mostly cloudy, with a low around 48. West southwest wind 5 to 10 mph becoming light south southwest after midnight. New precipitation amounts of less than a tenth of an inch possible.

    Low: 48 °F

    Chance Rain

  • Monday

    Monday: A 20 percent chance of rain after 11am. Mostly sunny, with a high near 65.

    High: 65 °F

    Slight Chance
    Rain

  • Monday Night

    Monday Night: Mostly clear, with a low around 48.

    Low: 48 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 66.

    High: 66 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 47.

    Low: 47 °F

    Mostly Clear

Detailed Forecast

Tonight
Rain and thunderstorms likely before 2am, then a slight chance of rain between 2am and 5am. Mostly cloudy, with a low around 54. South southwest wind around 7 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Saturday
Rain and thunderstorms likely before 3pm, then a chance of showers and thunderstorms between 3pm and 4pm, then showers and possibly a thunderstorm after 4pm. High near 64. South wind 7 to 17 mph, with gusts as high as 28 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Saturday Night
Showers and possibly a thunderstorm. Low around 49. South southwest wind 10 to 16 mph, with gusts as high as 28 mph. Chance of precipitation is 100%. New rainfall amounts between a half and three quarters of an inch possible.
Sunday
Showers and possibly a thunderstorm. High near 61. Southwest wind 10 to 13 mph, with gusts as high as 22 mph. Chance of precipitation is 90%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Sunday Night
A 40 percent chance of rain, mainly before 11pm. Mostly cloudy, with a low around 48. West southwest wind 5 to 10 mph becoming light south southwest after midnight. New precipitation amounts of less than a tenth of an inch possible.
Monday
A 20 percent chance of rain after 11am. Mostly sunny, with a high near 65.
Monday Night
Mostly clear, with a low around 48.
Tuesday
Sunny, with a high near 66.
Tuesday Night
Mostly clear, with a low around 47.
Wednesday
Sunny, with a high near 68.
Wednesday Night
Partly cloudy, with a low around 48.
Thursday
Sunny, with a high near 71.
Thursday Night
Mostly clear, with a low around 47.
Friday
Sunny, with a high near 73.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Castro Valley CA
 37.71°N 122.08°W (Elev. 397 ft)
Last Update:
2:57 pm PDT Apr 10, 2026
Forecast Valid:
9pm PDT Apr 10, 2026-6pm PDT Apr 17, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation