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

24°F

-4°C

Humidity 55%
Wind Speed NW 8 mph
Barometer 30.07 in (1018.4 mb)
Dewpoint 10°F (-12°C)
Visibility 10.00 mi
Wind Chill15°F (-9°C)
Last update 2 Feb 10:56 pm EST
Extended Forecast for

Port Jefferson NY

  • Tonight

    Tonight: Mostly clear, with a low around 13. Wind chill values between 5 and 10. Northwest wind 6 to 8 mph.

    Low: 13 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 33. Wind chill values between 5 and 15. West wind 6 to 9 mph.

    High: 33 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: A slight chance of light snow between 1am and 4am. Mostly cloudy, with a low around 20. Southwest wind 6 to 8 mph. Chance of precipitation is 20%.

    Low: 20 °F

    Mostly Cloudy
    then Slight
    Chance Light
    Snow

  • Wednesday

    Wednesday: Mostly sunny, with a high near 32. Wind chill values between 10 and 20. Northwest wind 7 to 10 mph.

    High: 32 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 16. Northwest wind around 8 mph.

    Low: 16 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 27.

    High: 27 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 16.

    Low: 16 °F

    Partly Cloudy

  • Friday

    Friday: A 30 percent chance of snow after 1pm. Partly sunny, with a high near 29.

    High: 29 °F

    Partly Sunny
    then Chance
    Snow

  • Friday Night

    Friday Night: A 30 percent chance of snow before 1am. Mostly cloudy, with a low around 11. Breezy.

    Low: 11 °F

    Chance Snow
    and Breezy

Detailed Forecast

Tonight
Mostly clear, with a low around 13. Wind chill values between 5 and 10. Northwest wind 6 to 8 mph.
Tuesday
Mostly sunny, with a high near 33. Wind chill values between 5 and 15. West wind 6 to 9 mph.
Tuesday Night
A slight chance of light snow between 1am and 4am. Mostly cloudy, with a low around 20. Southwest wind 6 to 8 mph. Chance of precipitation is 20%.
Wednesday
Mostly sunny, with a high near 32. Wind chill values between 10 and 20. Northwest wind 7 to 10 mph.
Wednesday Night
Partly cloudy, with a low around 16. Northwest wind around 8 mph.
Thursday
Mostly sunny, with a high near 27.
Thursday Night
Partly cloudy, with a low around 16.
Friday
A 30 percent chance of snow after 1pm. Partly sunny, with a high near 29.
Friday Night
A 30 percent chance of snow before 1am. Mostly cloudy, with a low around 11. Breezy.
Saturday
Mostly sunny and cold, with a high near 18. Windy.
Saturday Night
Partly cloudy, 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 11. Blustery.
Monday
Mostly sunny, with a high near 22.
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:
1:22 pm EST Feb 2, 2026
Forecast Valid:
11pm EST Feb 2, 2026-6pm EST Feb 9, 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