Third Napa Slough Weather Forecast

    • 59
    • 90

    Increasing Clouds

    • 59
    • 77

    Chance Rain Showers

    • 58
    • 77

    Chance Rain Showers

    • 57
    • 81

    Mostly Sunny

    • 58
    • 84

    Mostly Sunny

    • 60
    • 88

    Chance Rain Showers

    • 59
    • 78

    Slight Chance Rain Showers

Today 17 Sep North Bay Interior Valleys

Sunny. Highs in the lower 80s to mid 90s. Southwest Winds up to 5 Mph increasing to 10 to 15 Mph in the afternoon.

Tonight 17 Sep North Bay Interior Valleys

Partly cloudy. Lows in the 50s to mid 60s. Southwest Winds 5 to 10 Mph.

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  • Temperature Real-Time

Third Napa Slough Temperature Statistics

September Temperature

Napa, Napa County Airport (6.2 miles)

  • Lowest 14 September, 2025

    48 °F

  • Average September

    66.1 °F

  • Highest 15 September, 2025

    91 °F

Climate (2020–Present)

Napa, Napa County Airport (6.2 miles)

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  • Average Low 2020–2025

    46.9 °F

  • Average 2020–2025

    58.1 °F

  • Average High 2020–2025

    70.5 °F
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