Napa County Regional Park District - Lake Hennessey City Recreation Area Weather Forecast

    • 57
    • 86

    Chance Rain Showers

    • 55
    • 80

    Slight Chance Rain Showers

    • 56
    • 84

    Mostly Sunny

    • 59
    • 88

    Sunny

    • 59
    • 94

    Mostly Sunny

    • 57
    • 84

    Slight Chance Rain Showers

Today 18 Sep North Bay Interior Valleys

Mostly cloudy. A slight chance of Showers. Isolated Thunderstorms in the afternoon. Highs in the upper 60s to mid 80s. South Winds 10 to 15 Mph.

Tonight 18 Sep North Bay Interior Valleys

Mostly cloudy. A slight chance of Showers in the evening. Isolated Thunderstorms. A chance of Showers after midnight. Patchy fog after midnight. Lows in the mid 50s to lower 60s. Southwest Winds 5 to 10 Mph.

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Napa County Regional Park District - Lake Hennessey City Recreation Area Temperature Statistics

September Temperature

Napa, Napa County Airport (19.9 miles)

  • Lowest 14 September, 2025

    48 °F

  • Average September

    66.3 °F

  • Highest 15 September, 2025

    91 °F

Climate (2020–Present)

Napa, Napa County Airport (19.9 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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