Port Jefferson Harbor Weather Forecast

    • 33
    • 35

    Chance Rain

    • 35
    • 42

    Slight Chance Rain

    • 30
    • 40

    Mostly Cloudy

    • 23
    • 32

    Partly Sunny

    • 36
    • 38

    Chance Snow

    • 40
    • 46

    Chance Rain

Today 5 Dec Northwest Suffolk

Mostly cloudy. Highs in the mid 30s. East Winds around 5 Mph.

Tonight 5 Dec Northwest Suffolk

Cloudy. A slight chance of light snow and freezing drizzle late this Evening, then a chance of freezing drizzle and drizzle after midnight. Lows in the upper 20s. Northeast Winds around 5 Mph. Chance of precipitation 20 percent.

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Port Jefferson Harbor Temperature Statistics

December Temperature

Islip, Long Island Mac Arthur Airport (11.2 miles)

  • Lowest 3 December, 2025

    28 °F

  • Average December

    38.2 °F

  • Highest 1 December, 2025

    46 °F

Climate (2020–Present)

Islip, Long Island Mac Arthur Airport (11.2 miles)

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  • Average Low 2020–2025

    47.5 °F

  • Average 2020–2025

    55.3 °F

  • Average High 2020–2025

    63.1 °F
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