Great South Bay Weather Forecast

    • 72
    • 79

    Rain Showers Likely

    • 69
    • 81

    Partly Sunny

    • 64
    • 78

    Mostly Sunny

    • 65
    • 72

    Mostly Sunny

    • 68
    • 74

    Partly Sunny

    • 68
    • 75

    Partly Sunny

Today 3 Sep Southwest Suffolk

Mostly cloudy. A chance of Showers, mainly early. Humid with Highs in the lower 80s. Southwest Winds around 5 Mph, increasing to 10 to 15 Mph. Chance of rain 50 percent.

Tonight 3 Sep Southwest Suffolk

Mostly cloudy with a chance of Showers with a slight chance of Thunderstorms. Humid with Lows around 70. West Winds 5 to 10 Mph. Chance of rain 40 percent.

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  • Temperature Real-Time

Great South Bay Temperature Statistics

September Temperature

Islip, Long Island Mac Arthur Airport (8.1 miles)

  • Lowest 1 September, 2026

    66 °F

  • Average September

    71.3 °F

  • Highest 1 September, 2026

    78.1 °F

Climate (2021–2026)

Islip, Long Island Mac Arthur Airport (8.1 miles)

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  • Average Low 2021–2026

    47.2 °F

  • Average 2021–2026

    55.2 °F

  • Average High 2021–2026

    63.1 °F
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