Saint Johns River - Great Marsh Island Weather Forecast

    • 76
    • 88

    Slight Chance Rain Showers

    • 75
    • 87

    Chance Thunderstorms

    • 74
    • 84

    Rain Showers

    • 73
    • 81

    Rain Showers

    • 73
    • 83

    Rain Showers Likely

    • 74
    • 83

    Chance Thunderstorms

    • 74
    • 83

    Chance Thunderstorms

Today 6 Sep Coastal Duval

Mostly sunny with a 20 percent chance of Showers. Highs in the upper 80s. East Winds 10 to 15 Mph.

Tonight 6 Sep Coastal Duval

Mostly cloudy with a 20 percent chance of Showers. Lows in the mid 70s. East Winds 10 to 15 Mph.

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Saint Johns River - Great Marsh Island Temperature Statistics

September Temperature

Mayport Naval Station - Adm David L. McDonald Field (2.5 miles)

  • Lowest 3 September, 2025

    73.9 °F

  • Average September

    79.2 °F

  • Highest 4 September, 2025

    84.9 °F

Climate (2020–Present)

Mayport Naval Station - Adm David L. McDonald Field (2.5 miles)

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  • Average Low 2020–2025

    65.8 °F

  • Average 2020–2025

    72.8 °F

  • Average High 2020–2025

    80.1 °F
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