Great South Bay Weather Forecast

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    Rain Showers

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    Chance Rain Showers

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    Chance Rain Showers

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    Chance Rain Showers

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    Chance Rain Showers

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    Chance Rain Showers

Today 20 Sep Southwest Suffolk

Rain. Highs in the upper 60s. Southeast Winds 10 to 15 Mph with Gusts up to 25 Mph. Chance of rain near 100 percent.

Tonight 20 Sep Southwest Suffolk

Periods of rain with a slight chance of Thunderstorms. Some Thunderstorms may produce heavy rainfall. Lows in the lower 60s. South Winds 10 to 15 Mph, becoming north after midnight. Gusts up to 25 Mph. Chance of rain 90 percent.

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Great South Bay Temperature Statistics

September Temperature

Islip, Long Island Mac Arthur Airport (8.1 miles)

  • Lowest 15 September, 2026

    52.6 °F

  • Average September

    71.3 °F

  • Highest 10 September, 2026

    86.6 °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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