Sonoma Mountain Weather Forecast

    • 69
    • 93

    Decreasing Clouds

    • 61
    • 83

    Partly Sunny

    • 59
    • 76

    Mostly Sunny

    • 55
    • 68

    Mostly Sunny

    • 57
    • 74

    Mostly Sunny

    • 54
    • 75

    Mostly Sunny

    • 53
    • 67

    Partly Sunny

Today 9 Sep North Bay Interior Valleys

Partly cloudy late in the morning then becoming sunny. Highs upper 80s to 103. Southwest Winds up to 5 Mph increasing to west 10 to 15 Mph in the afternoon.

Tonight 9 Sep North Bay Interior Valleys

Mostly clear in the evening then becoming partly cloudy. Lows in the 60s to lower 70s. West Winds 5 to 10 Mph.

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Sonoma Mountain Temperature Statistics

September Temperature

Petaluma Municipal Airport (4.3 miles)

  • Lowest 7 September, 2026

    44.6 °F

  • Average September

    62 °F

  • Highest 7 September, 2026

    87.8 °F

Climate (2021–2026)

Petaluma Municipal Airport (4.3 miles)

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  • Average Low 2021–2026

    44.7 °F

  • Average 2021–2026

    55.2 °F

  • Average High 2021–2026

    68.5 °F
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