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National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce
7-Day Forecast 37.69°N 122.07°W (Text-Only)
NWS Forecast for: Castro Valley CA
Issued by: National Weather Service San Francisco Bay Area/Monterey, CA
Last Update: 7:35 pm PST Dec 4, 2025		Print

  • Tonight

    Tonight: Mostly clear, with a low around 43. Light east wind.

    Low: 43 °F

    Mostly Clear


  • Friday

    Friday: Sunny, with a high near 64. Calm wind becoming northwest around 5 mph in the afternoon.

    High: 64 °F

    Sunny


  • Friday
    Night

    Friday Night: Partly cloudy, with a low around 46. Calm wind.

    Low: 46 °F

    Partly Cloudy


  • Saturday

    Saturday: Sunny, with a high near 64. Calm wind becoming west northwest around 5 mph in the afternoon.

    High: 64 °F

    Sunny


  • Saturday
    Night

    Saturday Night: Partly cloudy, with a low around 48. Light and variable wind.

    Low: 48 °F

    Partly Cloudy


  • Sunday

    Sunday: Partly sunny, with a high near 64.

    High: 64 °F

    Partly Sunny


  • Sunday
    Night

    Sunday Night: Partly cloudy, with a low around 47.

    Low: 47 °F

    Partly Cloudy


  • Monday

    Monday: Patchy fog before 9am. Otherwise, mostly sunny, with a high near 65.

    High: 65 °F

    Patchy Fog
    then Mostly
    Sunny

  • Monday
    Night

    Monday Night: Partly cloudy, with a low around 47.

    Low: 47 °F

    Partly Cloudy




    • Tonight: Mostly clear, with a low around 43. Light east wind.

    Friday: Sunny, with a high near 64. Calm wind becoming northwest around 5 mph in the afternoon.

    Friday Night: Partly cloudy, with a low around 46. Calm wind.

    Saturday: Sunny, with a high near 64. Calm wind becoming west northwest around 5 mph in the afternoon.

    Saturday Night: Partly cloudy, with a low around 48. Light and variable wind.

    Sunday: Partly sunny, with a high near 64.

    Sunday Night: Partly cloudy, with a low around 47.

    Monday: Patchy fog before 9am. Otherwise, mostly sunny, with a high near 65.

    Monday Night: Partly cloudy, with a low around 47.

    Tuesday: Mostly sunny, with a high near 65.

    Tuesday Night: Partly cloudy, with a low around 48.

    Wednesday: Mostly sunny, with a high near 67.

    Wednesday Night: Partly cloudy, with a low around 49.

    Thursday: Mostly sunny, with a high near 67.


    Castro Valley CA
     37.69°N 122.07°W (Elev. 197 ft)

    Visit your local NWS office at: https://www.weather.gov/mtr