Marathon Weather Forecast

    • 80
    • 88

    Chance Rain Showers

    • 78
    • 88

    Chance Thunderstorms

    • 78
    • 87

    Rain Showers Likely

    • 79
    • 87

    Rain Showers Likely

    • 79
    • 87

    Rain Showers Likely

    • 80
    • 87

    Rain Showers Likely

Today 15 Sep Monroe Middle Keys

Mostly sunny with a chance of Showers and a slight chance of Thunderstorms. Highs near 90. Variable Winds near 5 Mph, becoming east to southeast. Chance of rain 30 percent.

Tonight 15 Sep Monroe Middle Keys

Partly cloudy with a chance of Showers and a slight chance of Thunderstorms. Lows near 80. Northeast to east Winds 5 to 10 Mph. Chance of rain 30 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Marathon Temperature Statistics

September Temperature

The Florida Keys - Marathon International Airport (2.5 miles)

  • Lowest 13 September, 2025

    73.9 °F

  • Average September

    83.4 °F

  • Highest 11 September, 2025

    89.1 °F

Climate (2020–Present)

The Florida Keys - Marathon International Airport (2.5 miles)

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  • Average Low 2020–2025

    75.4 °F

  • Average 2020–2025

    80 °F

  • Average High 2020–2025

    85.1 °F
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