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

Hazardous Weather Conditions

Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

Fair

13°F

-11°C

Humidity 59%
Wind Speed W 8 mph
Barometer 30.11 in (1019.7 mb)
Dewpoint 1°F (-17°C)
Visibility 10.00 mi
Wind Chill2°F (-17°C)
Last update 28 Jan 5:56 am EST
Extended Forecast for

Port Jefferson NY

  • Today

    Today: Increasing clouds, with a high near 23. Wind chill values between zero and 10. West wind 9 to 15 mph.

    High: 23 °F

    Increasing
    Clouds

  • Tonight

    Tonight: Mostly cloudy, with a low around 15. Wind chill values between 5 and 10. West wind 10 to 13 mph becoming northwest after midnight.

    Low: 15 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 22. Wind chill values between zero and 10. West wind 13 to 16 mph.

    High: 22 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 12. Wind chill values between -5 and 5. Blustery, with a west wind 17 to 20 mph.

    Low: 12 °F

    Mostly Clear
    and Blustery
    then Mostly
    Clear

  • Friday

    Friday: Sunny and cold, with a high near 19. West wind around 16 mph.

    High: 19 °F

    Cold

  • Friday Night

    Friday Night: Mostly clear, with a low around 9.

    Low: 9 °F

    Mostly Clear

  • Saturday

    Saturday: Mostly sunny, with a high near 21.

    High: 21 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: A 30 percent chance of snow after 1am. Mostly cloudy, with a low around 18. Windy.

    Low: 18 °F

    Mostly Cloudy
    and Blustery
    then Chance
    Snow and
    Windy

  • Sunday

    Sunday: A 50 percent chance of snow. Cloudy, with a high near 27. Windy.

    High: 27 °F

    Chance Snow
    and Windy

Detailed Forecast

Today
Increasing clouds, with a high near 23. Wind chill values between zero and 10. West wind 9 to 15 mph.
Tonight
Mostly cloudy, with a low around 15. Wind chill values between 5 and 10. West wind 10 to 13 mph becoming northwest after midnight.
Thursday
Mostly sunny, with a high near 22. Wind chill values between zero and 10. West wind 13 to 16 mph.
Thursday Night
Mostly clear, with a low around 12. Wind chill values between -5 and 5. Blustery, with a west wind 17 to 20 mph.
Friday
Sunny and cold, with a high near 19. West wind around 16 mph.
Friday Night
Mostly clear, with a low around 9.
Saturday
Mostly sunny, with a high near 21.
Saturday Night
A 30 percent chance of snow after 1am. Mostly cloudy, with a low around 18. Windy.
Sunday
A 50 percent chance of snow. Cloudy, with a high near 27. Windy.
Sunday Night
A 30 percent chance of snow before 1am. Mostly cloudy, with a low around 21. Windy.
Monday
Mostly sunny, with a high near 31. Blustery.
Monday Night
Partly cloudy, with a low around 22.
Tuesday
Mostly sunny, with a high near 31.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.96°N 73.08°W (Elev. 3 ft)
Last Update:
1:25 am EST Jan 28, 2026
Forecast Valid:
6am EST Jan 28, 2026-6pm EST Feb 3, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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