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.

A Few Clouds

19°F

-7°C

Humidity 43%
Wind Speed W 9 mph
Barometer 30.09 in (1019.0 mb)
Dewpoint 0°F (-18°C)
Visibility 10.00 mi
Wind Chill8°F (-13°C)
Last update 29 Jan 6:56 pm EST
Extended Forecast for

Port Jefferson NY

Cold Weather Advisory January 30, 12:00am until January 30, 10:00am
Click here for hazard details and duration
Cold Weather Advisory

  • Tonight

    Tonight: Mostly clear, with a low around 8. Wind chill values between -10 and zero. Blustery, with a northwest wind 18 to 20 mph.

    Low: 8 °F

    Mostly Clear
    and Blustery

  • Friday

    Friday: Mostly sunny and cold, with a high near 17. Wind chill values between -10 and zero. West wind 15 to 17 mph.

    High: 17 °F

    Cold

  • Friday Night

    Friday Night: Partly cloudy, with a low around 10. Wind chill values between -5 and zero. Northwest wind 9 to 16 mph.

    Low: 10 °F

    Partly Cloudy

  • Saturday

    Saturday: Partly sunny and cold, with a high near 20. Wind chill values between -5 and 5. North wind around 10 mph.

    High: 20 °F

    Cold

  • Saturday Night

    Saturday Night: A 30 percent chance of snow after 1am. Mostly cloudy, with a low around 15. Windy, with a north wind 15 to 20 mph increasing to 28 to 33 mph after midnight.

    Low: 15 °F

    Mostly Cloudy
    and Blustery
    then Chance
    Snow and
    Windy

  • Sunday

    Sunday: A 40 percent chance of snow. Cloudy, with a high near 25. Windy.

    High: 25 °F

    Chance Snow
    and Windy

  • Sunday Night

    Sunday Night: Mostly cloudy, with a low around 20. Blustery.

    Low: 20 °F

    Mostly Cloudy
    and Blustery

  • Monday

    Monday: Mostly sunny, with a high near 30. Blustery.

    High: 30 °F

    Mostly Sunny
    and Blustery
    then Mostly
    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 21.

    Low: 21 °F

    Mostly Clear

Detailed Forecast

Tonight
Mostly clear, with a low around 8. Wind chill values between -10 and zero. Blustery, with a northwest wind 18 to 20 mph.
Friday
Mostly sunny and cold, with a high near 17. Wind chill values between -10 and zero. West wind 15 to 17 mph.
Friday Night
Partly cloudy, with a low around 10. Wind chill values between -5 and zero. Northwest wind 9 to 16 mph.
Saturday
Partly sunny and cold, with a high near 20. Wind chill values between -5 and 5. North wind around 10 mph.
Saturday Night
A 30 percent chance of snow after 1am. Mostly cloudy, with a low around 15. Windy, with a north wind 15 to 20 mph increasing to 28 to 33 mph after midnight.
Sunday
A 40 percent chance of snow. Cloudy, with a high near 25. Windy.
Sunday Night
Mostly cloudy, with a low around 20. Blustery.
Monday
Mostly sunny, with a high near 30. Blustery.
Monday Night
Mostly clear, with a low around 21.
Tuesday
Mostly sunny, with a high near 31.
Tuesday Night
Partly cloudy, with a low around 22.
Wednesday
Mostly sunny, with a high near 29.
Wednesday Night
Partly cloudy, with a low around 19.
Thursday
A 30 percent chance of snow. Partly sunny, with a high near 29.
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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:
1:13 pm EST Jan 29, 2026
Forecast Valid:
7pm EST Jan 29, 2026-6pm EST Feb 5, 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