Mill Valley Weather Forecast

    • 49
    • 64

    Mostly Cloudy

    • 47
    • 64

    Partly Sunny

    • 51
    • 73

    Mostly Sunny

    • 57
    • 84

    Sunny

    • 57
    • 82

    Mostly Sunny

    • 56
    • 77

    Mostly Sunny

    • 56
    • 78

    Mostly Sunny

Today 26 Sep North Bay Interior Valleys

Mostly cloudy. Highs in the 60s to 70s. South Winds 5 to 10 Mph.

Tonight 26 Sep North Bay Interior Valleys

Mostly cloudy. Patchy fog after midnight. Lows in the upper 40s to mid 50s. Southwest Winds 5 to 10 Mph.

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Mill Valley Temperature Statistics

September Temperature

Novato / Gnoss Field (16.2 miles)

  • Lowest 6 September, 2026

    48.2 °F

  • Average September

    65.8 °F

  • Highest 9 September, 2026

    100.4 °F

Climate (2021–2026)

Novato / Gnoss Field (16.2 miles)

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  • Average Low 2021–2026

    47 °F

  • Average 2021–2026

    57.8 °F

  • Average High 2021–2026

    72.4 °F
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