Great South Bay Weather Forecast

    • 68
    • 81

    Rain Showers

    • 70
    • 77

    Rain Showers Likely

    • 72
    • 77

    Rain Showers

    • 71
    • 79

    Slight Chance Thunderstorms

    • 69
    • 79

    Mostly Sunny

    • 70
    • 77

    Partly Sunny

Today 20 Aug Southwest Suffolk

Sunny this Morning, then partly sunny with a chance of Showers this afternoon. Highs in the lower 80s. North Winds around 5 Mph, becoming south this afternoon. Chance of rain 50 percent.

Tonight 20 Aug Southwest Suffolk

Mostly cloudy. Showers with a slight chance of Thunderstorms in the Evening, then a chance of Showers after midnight. Lows in the mid 60s. Northeast Winds 10 to 15 Mph. Chance of rain 90 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Great South Bay Temperature Statistics

August Temperature

Islip, Long Island Mac Arthur Airport (8.1 miles)

  • Lowest 4 August, 2026

    63.6 °F

  • Average August

    77.5 °F

  • Highest 7 August, 2026

    91.7 °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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