Castro Valley Weather Forecast

    • 59
    • 80

    Increasing Clouds

    • 58
    • 77

    Partly Sunny

    • 58
    • 78

    Partly Sunny

    • 58
    • 79

    Mostly Sunny

    • 59
    • 82

    Mostly Sunny

    • 59
    • 80

    Partly Sunny

Today 26 Aug San Francisco Bay Shoreline

Mostly cloudy in the morning then becoming sunny. Highs in the 70s to lower 80s. Northwest Winds 5 to 15 Mph.

Tonight 26 Aug San Francisco Bay Shoreline

Mostly clear in the evening then becoming mostly cloudy. Lows around 60. Northwest Winds 10 to 15 Mph decreasing to around 5 Mph after midnight.

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  • Temperature Real-Time

Castro Valley Temperature Statistics

August Temperature

Hayward, Hayward Air Terminal (3.1 miles)

  • Lowest 4 August, 2025

    56.6 °F

  • Average August

    65.2 °F

  • Highest 20 August, 2025

    85.6 °F

Climate (2020–Present)

Hayward, Hayward Air Terminal (3.1 miles)

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  • Average Low 2020–2025

    52 °F

  • Average 2020–2025

    59.3 °F

  • Average High 2020–2025

    69 °F
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