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.

A Few Clouds

18°F

-8°C

Humidity 47%
Wind Speed NW 14 G 24 mph
Barometer 29.96 in (1014.5 mb)
Dewpoint 1°F (-17°C)
Visibility 10.00 mi
Wind Chill4°F (-16°C)
Last update 2 Feb 8:56 am EST
Extended Forecast for

Port Jefferson NY

  • Today

    Today: Sunny, with a high near 29. Wind chill values between 10 and 20. Northwest wind 8 to 10 mph.

    High: 29 °F

    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 15. Northwest wind 3 to 5 mph.

    Low: 15 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 30. Wind chill values between 10 and 20. Southwest wind 3 to 7 mph.

    High: 30 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: A 20 percent chance of snow after 1am. Mostly cloudy, with a low around 22. Light southwest wind.

    Low: 22 °F

    Mostly Cloudy
    then Slight
    Chance Snow

  • Wednesday

    Wednesday: Mostly cloudy, then gradually becoming sunny, with a high near 31. Northwest wind 3 to 8 mph.

    High: 31 °F

    Decreasing
    Clouds

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 14.

    Low: 14 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 28.

    High: 28 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 13.

    Low: 13 °F

    Partly Cloudy

  • Friday

    Friday: A 30 percent chance of snow after 1pm. Mostly cloudy, with a high near 30.

    High: 30 °F

    Partly Sunny
    then Chance
    Snow

Detailed Forecast

Today
Sunny, with a high near 29. Wind chill values between 10 and 20. Northwest wind 8 to 10 mph.
Tonight
Mostly clear, with a low around 15. Northwest wind 3 to 5 mph.
Tuesday
Mostly sunny, with a high near 30. Wind chill values between 10 and 20. Southwest wind 3 to 7 mph.
Tuesday Night
A 20 percent chance of snow after 1am. Mostly cloudy, with a low around 22. Light southwest wind.
Wednesday
Mostly cloudy, then gradually becoming sunny, with a high near 31. Northwest wind 3 to 8 mph.
Wednesday Night
Partly cloudy, with a low around 14.
Thursday
Mostly sunny, with a high near 28.
Thursday Night
Partly cloudy, with a low around 13.
Friday
A 30 percent chance of snow after 1pm. Mostly cloudy, with a high near 30.
Friday Night
A 30 percent chance of snow before 1am. Mostly cloudy, with a low around 9.
Saturday
Mostly sunny and cold, with a high near 17. Blustery.
Saturday Night
Partly cloudy, with a low around 4. Blustery.
Sunday
Mostly sunny and cold, with a high near 19. Blustery.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.93°N 73.06°W (Elev. 161 ft)
Last Update:
12:53 am EST Feb 2, 2026
Forecast Valid:
10am EST Feb 2, 2026-6pm EST Feb 8, 2026
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation