Great South Bay Weather Forecast

    • 65
    • 77

    Chance Rain Showers

    • 60
    • 72

    Mostly Sunny

    • 66
    • 75

    Mostly Sunny

    • 69
    • 76

    Partly Sunny

    • 72
    • 76

    Chance Rain Showers

    • 67
    • 80

    Partly Sunny

Today 5 Sep Southwest Suffolk

Sunny. Highs in the upper 70s. North Winds 5 to 10 Mph.

Tonight 5 Sep Southwest Suffolk

Partly cloudy in the Evening, then becoming mostly cloudy. Scattered Showers. Lows around 60. Northeast Winds 5 to 10 Mph. Chance of rain 40 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Great South Bay Temperature Statistics

September Temperature

Islip, Long Island Mac Arthur Airport (8.1 miles)

  • Lowest 2 September, 2026

    65.6 °F

  • Average September

    72.9 °F

  • Highest 3 September, 2026

    84 °F

Climate (2021–2026)

Islip, Long Island Mac Arthur Airport (8.1 miles)

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  • Average Low 2021–2026

    47.3 °F

  • Average 2021–2026

    55.2 °F

  • Average High 2021–2026

    63.1 °F
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