Marathon Weather Forecast

    • 83
    • 90

    Chance Thunderstorms

    • 83
    • 90

    Chance Rain Showers

    • 84
    • 90

    Chance Rain Showers

    • 83
    • 90

    Chance Thunderstorms

    • 83
    • 90

    Thunderstorms Likely

    • 83
    • 90

    Chance Thunderstorms

Today 8 Sep Monroe Middle Keys

Partly cloudy with a chance of Showers and a slight chance of Thunderstorms. Highs in the lower 90s. Variable Winds near 5 Mph. Chance of rain 40 percent.

Tonight 8 Sep Monroe Middle Keys

Partly cloudy with a chance of Showers and a slight chance of Thunderstorms. Lows in the lower 80s. Northeast to east Winds near 5 Mph, becoming east 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 4 September, 2026

    78.7 °F

  • Average September

    86.5 °F

  • Highest 1 September, 2026

    92.6 °F

Climate (2021–2026)

The Florida Keys - Marathon International Airport (2.5 miles)

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  • Average Low 2021–2026

    75.5 °F

  • Average 2021–2026

    80.1 °F

  • Average High 2021–2026

    85.1 °F
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