Smithtown Weather Forecast

    • 58
    • 77

    Mostly Sunny

    • 65
    • 77

    Chance Rain Showers

    • 68
    • 81

    Mostly Sunny

    • 60
    • 82

    Rain Showers Likely

    • 57
    • 74

    Slight Chance Rain Showers

    • 57
    • 75

    Mostly Sunny

Today 3 Sep Northwest Suffolk

Patchy fog this morning. Mostly sunny. Highs in the mid 70s. Northeast Winds around 5 Mph, becoming southeast this afternoon.

Tonight 3 Sep Northwest Suffolk

Mostly clear. Patchy fog after midnight. Lows in the upper 50s. South Winds around 5 Mph.

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Smithtown Temperature Statistics

September Temperature

Islip, Long Island Mac Arthur Airport (6.2 miles)

  • Lowest 1 September, 2025

    59 °F

  • Average September

    68.1 °F

  • Highest 1 September, 2025

    77 °F

Climate (2020–Present)

Islip, Long Island Mac Arthur Airport (6.2 miles)

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  • Average Low 2020–2025

    47.4 °F

  • Average 2020–2025

    55.2 °F

  • Average High 2020–2025

    63.1 °F
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