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.

Overcast

21°F

-6°C

Humidity 68%
Wind Speed Calm
Barometer 30.15 in (1021.1 mb)
Dewpoint 12°F (-11°C)
Visibility 10.00 mi
Last update 3 Feb 9:56 pm EST
Extended Forecast for

Port Jefferson NY

  • Tonight

    Tonight: Partly cloudy, with a low around 19. Wind chill values between 10 and 15. West wind around 9 mph.

    Low: 19 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Sunny, with a high near 32. Wind chill values between 5 and 15. Northwest wind around 10 mph.

    High: 32 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 19. Wind chill values between 10 and 15. Northwest wind 6 to 8 mph.

    Low: 19 °F

    Partly Cloudy

  • Thursday

    Thursday: Sunny, with a high near 29. Wind chill values between 10 and 20. Northwest wind around 9 mph.

    High: 29 °F

    Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 16. North wind 6 to 9 mph.

    Low: 16 °F

    Partly Cloudy

  • Friday

    Friday: Partly sunny, with a high near 27.

    High: 27 °F

    Partly Sunny

  • Friday Night

    Friday Night: A 50 percent chance of snow. Mostly cloudy, with a low around 15. Breezy.

    Low: 15 °F

    Chance Snow
    and Breezy

  • Saturday

    Saturday: Mostly sunny, with a high near 21. Windy.

    High: 21 °F

    Mostly Sunny
    and Windy

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 9. Windy.

    Low: 9 °F

    Mostly Clear
    and Windy

Detailed Forecast

Tonight
Partly cloudy, with a low around 19. Wind chill values between 10 and 15. West wind around 9 mph.
Wednesday
Sunny, with a high near 32. Wind chill values between 5 and 15. Northwest wind around 10 mph.
Wednesday Night
Partly cloudy, with a low around 19. Wind chill values between 10 and 15. Northwest wind 6 to 8 mph.
Thursday
Sunny, with a high near 29. Wind chill values between 10 and 20. Northwest wind around 9 mph.
Thursday Night
Partly cloudy, with a low around 16. North wind 6 to 9 mph.
Friday
Partly sunny, with a high near 27.
Friday Night
A 50 percent chance of snow. Mostly cloudy, with a low around 15. Breezy.
Saturday
Mostly sunny, with a high near 21. Windy.
Saturday Night
Mostly clear, with a low around 9. Windy.
Sunday
Mostly sunny and cold, with a high near 19. Blustery.
Sunday Night
Partly cloudy, with a low around 8. Blustery.
Monday
Mostly sunny, with a high near 22.
Monday Night
Partly cloudy, with a low around 15.
Tuesday
Mostly sunny, with a high near 28.
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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:
12:54 pm EST Feb 3, 2026
Forecast Valid:
10pm EST Feb 3, 2026-6pm EST Feb 10, 2026
 
Forecast Discussion
 
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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