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.

20°F

-7°C

Humidity 85%
Wind Speed N 15 mph
Barometer 29.71 in (1006.2 mb)
Dewpoint 16°F (-9°C)
Visibility 10.00 mi
Wind Chill6°F (-14°C)
Last update 26 Jan 1:56 am EST
Extended Forecast for

Port Jefferson NY

  • Overnight

    Overnight: A chance of snow and sleet before 4am, then a chance of snow. Cloudy, with a low around 24. Wind chill values between 10 and 15. Blustery, with a north wind 15 to 21 mph. Chance of precipitation is 30%.

    Low: 24 °F

    Chance
    Snow/Sleet
    and Blustery

  • Monday

    Monday: A 40 percent chance of snow before 1pm. Patchy blowing snow after 3pm. Cloudy, with a high near 29. Wind chill values between 15 and 20. North wind 10 to 17 mph becoming west in the afternoon.

    High: 29 °F

    Chance Snow
    and Patchy
    Blowing Snow

  • Monday Night

    Monday Night: Mostly cloudy, then gradually becoming mostly clear, with a low around 17. Wind chill values between zero and 10. Windy, with a west wind 23 to 28 mph.

    Low: 17 °F

    Decreasing
    Clouds and
    Windy

  • Tuesday

    Tuesday: Increasing clouds and cold, with a steady temperature around 19. Wind chill values between zero and 5. Breezy, with a west wind 16 to 22 mph.

    High: 19 °F

    Sunny then
    Partly Sunny
    and Breezy

  • Tuesday Night

    Tuesday Night: Mostly clear, with a steady temperature around 18. Breezy, with a west wind 18 to 23 mph.

    Low: 18 °F

    Mostly Clear
    and Breezy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 22.

    High: 22 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 14.

    Low: 14 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 21.

    High: 21 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 10. Blustery.

    Low: 10 °F

    Mostly Clear
    and Blustery

Detailed Forecast

Overnight
A chance of snow and sleet before 4am, then a chance of snow. Cloudy, with a low around 24. Wind chill values between 10 and 15. Blustery, with a north wind 15 to 21 mph. Chance of precipitation is 30%.
Monday
A 40 percent chance of snow before 1pm. Patchy blowing snow after 3pm. Cloudy, with a high near 29. Wind chill values between 15 and 20. North wind 10 to 17 mph becoming west in the afternoon.
Monday Night
Mostly cloudy, then gradually becoming mostly clear, with a low around 17. Wind chill values between zero and 10. Windy, with a west wind 23 to 28 mph.
Tuesday
Increasing clouds and cold, with a steady temperature around 19. Wind chill values between zero and 5. Breezy, with a west wind 16 to 22 mph.
Tuesday Night
Mostly clear, with a steady temperature around 18. Breezy, with a west wind 18 to 23 mph.
Wednesday
Mostly sunny, with a high near 22.
Wednesday Night
Mostly cloudy, with a low around 14.
Thursday
Mostly sunny, with a high near 21.
Thursday Night
Mostly clear, with a low around 10. Blustery.
Friday
Mostly sunny and cold, with a high near 19.
Friday Night
Mostly clear, with a low around 12.
Saturday
Sunny, with a high near 24.
Saturday Night
Mostly clear, with a low around 16.
Sunday
Mostly sunny, with a high near 27.
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:
1:49 am EST Jan 26, 2026
Forecast Valid:
2am EST Jan 26, 2026-6pm EST Feb 1, 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