National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce
Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

Light Snow

31°F

-1°C

Humidity 59%
Wind Speed W 13 mph
Barometer 29.96 in (1014.6 mb)
Dewpoint 18°F (-8°C)
Visibility 10.00 mi
Wind Chill21°F (-6°C)
Last update 19 Jan 3:56 pm EST
Extended Forecast for

Port Jefferson NY

  • M.L.King Day

    M.L.King Day: A chance of flurries. Partly sunny, with a high near 31. Wind chill values between 15 and 20. Breezy, with a southwest wind around 22 mph.

    High: 31 °F

    Chance
    Flurries and
    Breezy

  • Tonight

    Tonight: A chance of flurries before 10pm. Mostly clear, with a low around 20. Wind chill values between 5 and 15. Windy, with a west wind 23 to 30 mph.

    Low: 20 °F

    Chance
    Flurries and
    Windy

  • Tuesday

    Tuesday: Sunny, with a high near 23. Wind chill values between 5 and 10. Breezy, with a west wind around 23 mph.

    High: 23 °F

    Sunny and
    Breezy

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 18. Wind chill values between 5 and 10. Breezy, with a west wind 17 to 22 mph decreasing to 10 to 15 mph after midnight.

    Low: 18 °F

    Mostly Clear
    and Breezy
    then Mostly
    Clear

  • Wednesday

    Wednesday: Increasing clouds, with a high near 38. South wind 9 to 17 mph.

    High: 38 °F

    Increasing
    Clouds

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a steady temperature around 36. Breezy.

    Low: 36 °F

    Mostly Cloudy
    and Breezy

  • Thursday

    Thursday: Mostly sunny, with a high near 41.

    High: 41 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 24.

    Low: 24 °F

    Partly Cloudy

  • Friday

    Friday: Partly sunny, with a high near 31. Breezy.

    High: 31 °F

    Partly Sunny
    then Partly
    Sunny and
    Breezy

Detailed Forecast

M.L.King Day
A chance of flurries. Partly sunny, with a high near 31. Wind chill values between 15 and 20. Breezy, with a southwest wind around 22 mph.
Tonight
A chance of flurries before 10pm. Mostly clear, with a low around 20. Wind chill values between 5 and 15. Windy, with a west wind 23 to 30 mph.
Tuesday
Sunny, with a high near 23. Wind chill values between 5 and 10. Breezy, with a west wind around 23 mph.
Tuesday Night
Mostly clear, with a low around 18. Wind chill values between 5 and 10. Breezy, with a west wind 17 to 22 mph decreasing to 10 to 15 mph after midnight.
Wednesday
Increasing clouds, with a high near 38. South wind 9 to 17 mph.
Wednesday Night
Mostly cloudy, with a steady temperature around 36. Breezy.
Thursday
Mostly sunny, with a high near 41.
Thursday Night
Partly cloudy, with a low around 24.
Friday
Partly sunny, with a high near 31. Breezy.
Friday Night
Mostly cloudy, with a low around 10. Blustery.
Saturday
Mostly cloudy and cold, with a high near 18.
Saturday Night
A 30 percent chance of snow. Mostly cloudy, with a low around 8.
Sunday
A 30 percent chance of snow. Mostly cloudy and cold, with a high near 19.
Sunday Night
A 30 percent chance of snow. Mostly cloudy, with a low around 9.
Monday
Partly sunny, with a high near 23.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.96°N 73.08°W (Elev. 3 ft)
Last Update:
3:36 pm EST Jan 19, 2026
Forecast Valid:
4pm EST Jan 19, 2026-6pm EST Jan 26, 2026
 
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Additional Resources

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