Great South Bay Weather Forecast

    • 65
    • 80

    Becoming Sunny

    • 62
    • 80

    Rain Showers

    • 64
    • 72

    Mostly Sunny

    • 67
    • 74

    Mostly Sunny

    • 68
    • 76

    Partly Sunny

    • 72
    • 75

    Slight Chance Rain Showers

Today 4 Sep Southwest Suffolk

Mostly sunny. Near steady temperature in the lower 80s. Northwest Winds around 10 Mph with Gusts up to 20 Mph.

Tonight 4 Sep Southwest Suffolk

Partly cloudy. Lows in the mid 60s. Northwest Winds 5 to 10 Mph.

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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

    64.9 °F

  • Average September

    70.8 °F

  • Highest 1 September, 2026

    78.7 °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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