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

30°F

-1°C

Humidity 41%
Wind Speed N 9 mph
Barometer 29.95 in (1014.3 mb)
Dewpoint 9°F (-13°C)
Visibility 10.00 mi
Wind Chill22°F (-6°C)
Last update 5 Feb 3:56 pm EST
Extended Forecast for

Port Jefferson NY

Extreme Cold Watch February 7, 06:00pm until February 8, 01:00pm
Click here for hazard details and duration
Extreme Cold Watch

  • Tonight

    Tonight: Increasing clouds, with a low around 17. Calm wind becoming northeast around 5 mph after midnight.

    Low: 17 °F

    Increasing
    Clouds

  • Friday

    Friday: Mostly cloudy, with a high near 28. Wind chill values between 10 and 20. North wind around 5 mph becoming calm in the afternoon.

    High: 28 °F

    Mostly Cloudy

  • Friday Night

    Friday Night: Snow, mainly after 1am. Steady temperature around 24. Light and variable wind. Chance of precipitation is 80%. New snow accumulation of less than one inch possible.

    Low: 24 °F

    Chance Snow
    then Snow

  • Saturday

    Saturday: Snow, mainly before 1pm. Temperature falling to around 15 by 5pm. Wind chill values between -5 and 5. Windy, with a northwest wind 6 to 16 mph increasing to 18 to 28 mph. Winds could gust as high as 48 mph. Chance of precipitation is 80%. New snow accumulation of around an inch possible.

    High: 23 °F⇓

    Snow and
    Windy

  • Saturday Night

    Saturday Night: Mostly cloudy, then gradually becoming mostly clear, with a low around 4. Windy, with a northwest wind 24 to 29 mph decreasing to 18 to 23 mph after midnight. Winds could gust as high as 43 mph.

    Low: 4 °F

    Decreasing
    Clouds and
    Windy

  • Sunday

    Sunday: Sunny and cold, with a high near 17.

    High: 17 °F

    Cold

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 7.

    Low: 7 °F

    Mostly Clear

  • Monday

    Monday: Mostly sunny, with a high near 24.

    High: 24 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 12.

    Low: 12 °F

    Partly Cloudy

Detailed Forecast

Tonight
Increasing clouds, with a low around 17. Calm wind becoming northeast around 5 mph after midnight.
Friday
Mostly cloudy, with a high near 28. Wind chill values between 10 and 20. North wind around 5 mph becoming calm in the afternoon.
Friday Night
Snow, mainly after 1am. Steady temperature around 24. Light and variable wind. Chance of precipitation is 80%. New snow accumulation of less than one inch possible.
Saturday
Snow, mainly before 1pm. Temperature falling to around 15 by 5pm. Wind chill values between -5 and 5. Windy, with a northwest wind 6 to 16 mph increasing to 18 to 28 mph. Winds could gust as high as 48 mph. Chance of precipitation is 80%. New snow accumulation of around an inch possible.
Saturday Night
Mostly cloudy, then gradually becoming mostly clear, with a low around 4. Windy, with a northwest wind 24 to 29 mph decreasing to 18 to 23 mph after midnight. Winds could gust as high as 43 mph.
Sunday
Sunny and cold, with a high near 17.
Sunday Night
Mostly clear, with a low around 7.
Monday
Mostly sunny, with a high near 24.
Monday Night
Partly cloudy, with a low around 12.
Tuesday
Mostly sunny, with a high near 29.
Tuesday Night
Mostly cloudy, with a low around 19.
Wednesday
A 30 percent chance of rain. Mostly sunny, with a high near 34.
Wednesday Night
Mostly cloudy, with a low around 25.
Thursday
Mostly cloudy, with a high near 35.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.93°N 73.06°W (Elev. 161 ft)
Last Update:
1:09 pm EST Feb 5, 2026
Forecast Valid:
4pm EST Feb 5, 2026-6pm EST Feb 12, 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