Lostmans River - Onion Key Weather Forecast

    • 55
    • 84

    Sunny

    • 57
    • 86

    Mostly Sunny

    • 60
    • 86

    Mostly Sunny

    • 61
    • 86

    Mostly Sunny

    • 62
    • 88

    Mostly Sunny

    • 63
    • 88

    Partly Sunny

    • 64
    • 82

    Chance Rain Showers

Today 23 Mar Mainland Monroe

Sunny. Highs in the mid 80s. North Winds around 5 Mph, becoming west this afternoon.

Tonight 23 Mar Mainland Monroe

Clear. Lows in the mid 50s. Northwest Winds around 5 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Lostmans River - Onion Key Temperature Statistics

March Temperature

Miami, Kendall-Tamiami Executive Airport (43.5 miles)

  • Lowest 17 March, 2026

    54.6 °F

  • Average March

    74.1 °F

  • Highest 12 March, 2026

    88.6 °F

Climate (2021–Present)

Miami, Kendall-Tamiami Executive Airport (43.5 miles)

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  • Average Low 2021–2026

    69.1 °F

  • Average 2021–2026

    77.1 °F

  • Average High 2021–2026

    85.7 °F
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