Guerneville Weather Forecast

    • 49
    • 65

    Rain

    • 49
    • 69

    Mostly Sunny

    • 50
    • 71

    Mostly Sunny

    • 50
    • 72

    Mostly Sunny

    • 55
    • 76

    Mostly Sunny

    • 54
    • 77

    Partly Sunny

Today 3 Sep North Bay Interior Valleys

Rain likely. Highs in the lower 60s to mid 70s. Southwest Winds 10 to 20 Mph.

Tonight 3 Sep North Bay Interior Valleys

Mostly cloudy. Patchy fog. A chance of rain. Lows in the 50s. South Winds up to 5 Mph.

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Guerneville Temperature Statistics

September Temperature

Santa Rosa, Santa Rosa Sonoma County Airport (9.3 miles)

  • Lowest 1 September, 2026

    53.1 °F

  • Average September

    62.2 °F

  • Highest 1 September, 2026

    71.1 °F

Climate (2021–2026)

Santa Rosa, Santa Rosa Sonoma County Airport (9.3 miles)

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  • Average Low 2021–2026

    45.9 °F

  • Average 2021–2026

    58.7 °F

  • Average High 2021–2026

    72.9 °F
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