Smithtown Weather Forecast

    • 65
    • 77

    Rain Showers

    • 65
    • 78

    Rain Showers

    • 56
    • 74

    Mostly Sunny

    • 57
    • 71

    Mostly Sunny

    • 62
    • 74

    Partly Sunny

    • 64
    • 78

    Partly Sunny

    • 60
    • 78

    Chance Rain Showers

Today 12 Sep Northwest Suffolk

Mostly sunny. Near steady temperature in the mid 70s. South Winds 5 to 10 Mph.

Tonight 12 Sep Northwest Suffolk

Mostly cloudy. A chance of Showers with a slight chance of Thunderstorms after midnight. Lows in the mid 60s. Southeast Winds 5 to 10 Mph. Chance of rain 50 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Smithtown Temperature Statistics

September Temperature

Islip, Long Island Mac Arthur Airport (6.2 miles)

  • Lowest 7 September, 2026

    56.6 °F

  • Average September

    72.8 °F

  • Highest 3 September, 2026

    85.6 °F

Climate (2021–2026)

Islip, Long Island Mac Arthur Airport (6.2 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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