Great South Bay Weather Forecast

    • 68
    • 81

    Increasing Clouds

    • 63
    • 76

    Decreasing Clouds

    • 71
    • 75

    Rain Showers Likely

    • 69
    • 77

    Rain Showers Likely

    • 64
    • 75

    Partly Sunny

    • 68
    • 72

    Mostly Sunny

    • 70
    • 76

    Slight Chance Rain Showers

Today 10 Sep Southwest Suffolk

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

Tonight 10 Sep Southwest Suffolk

Partly cloudy in the Evening, then becoming mostly cloudy. Lows in the upper 60s. West Winds 5 to 10 Mph, becoming north 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

    72.3 °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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