Great South Bay Weather Forecast

    • 60
    • 76

    Decreasing Clouds

    • 71
    • 75

    Rain Showers

    • 69
    • 77

    Rain Showers Likely

    • 63
    • 74

    Mostly Sunny

    • 65
    • 70

    Mostly Sunny

    • 68
    • 74

    Partly Sunny

    • 68
    • 76

    Chance Rain Showers

Today 11 Sep Southwest Suffolk

Mostly sunny. Near steady temperature in the upper 70s. Northwest Winds 5 to 10 Mph.

Tonight 11 Sep Southwest Suffolk

Mostly clear. Patchy fog after midnight. Lows around 60. West Winds around 5 Mph, becoming northeast around 5 Mph after midnight.

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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 7 September, 2026

    56.6 °F

  • Average September

    72.4 °F

  • Highest 3 September, 2026

    85.6 °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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