Great South Bay Weather Forecast

    • 57
    • 72

    Rain Showers Likely

    • 52
    • 62

    Rain Showers Likely

    • 52
    • 59

    Rain Showers

    • 52
    • 57

    Rain Showers

    • 54
    • 59

    Chance Rain Showers

    • 55
    • 63

    Slight Chance Rain Showers

Today 20 May Southwest Suffolk

Sunny this Morning, then partly sunny with a chance of Showers and Thunderstorms this afternoon. Highs in the lower 80s. Southwest Winds 10 to 15 Mph with Gusts up to 25 Mph. Chance of rain 50 percent.

Tonight 20 May Southwest Suffolk

Mostly cloudy. Showers likely with a chance of Thunderstorms in the Evening, then a chance of Showers after midnight. Lows in the upper 50s. West Winds 5 to 10 Mph, becoming north after midnight. Chance of rain 70 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Great South Bay Temperature Statistics

May Temperature

Islip, Long Island Mac Arthur Airport (8.1 miles)

  • Lowest 1 May, 2026

    40.6 °F

  • Average May

    57.5 °F

  • Highest 17 May, 2026

    82.9 °F

Climate (2021–Present)

Islip, Long Island Mac Arthur Airport (8.1 miles)

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  • Average Low 2021–2026

    47.3 °F

  • Average 2021–2026

    55.1 °F

  • Average High 2021–2026

    63 °F
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