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.

Mostly Cloudy and Breezy

34°F

1°C

Humidity 32%
Wind Speed W 22 G 39 mph
Barometer 29.62 in
Dewpoint 7°F (-14°C)
Visibility 10.00 mi
Wind Chill22°F (-6°C)
Last update 30 Dec 12:56 pm EST
Extended Forecast for

Port Jefferson NY

Wind Advisory December 30, 01:50pm until December 30, 06:00pm
Click here for hazard details and duration
Wind Advisory
  •  
    Wind Advisory December 30, 01:50pm until December 30, 06:00pm

    NOW until 6:00pm Tue

    Wind Advisory

  • This Afternoon

    High: 33 °F

    Mostly Cloudy
    and Windy

  • Tonight

    Tonight: Mostly cloudy, with a low around 28. Wind chill values between 15 and 20. Windy, with a west wind 22 to 30 mph.

    Low: 28 °F

    Mostly Cloudy
    and Windy

  • Wednesday

    Wednesday: Partly sunny, with a high near 34. Wind chill values between 15 and 25. Southwest wind 15 to 18 mph.

    High: 34 °F

    Partly Sunny

  • Wednesday Night

    Wednesday Night: Snow likely, mainly after 1am. Increasing clouds, with a steady temperature around 32. Wind chill values between 20 and 25. Southwest wind 15 to 18 mph. Chance of precipitation is 70%. New snow accumulation of less than one inch possible.

    Low: 32 °F

    Chance Snow
    then Snow
    Likely

  • New Year's Day

    New Year's Day: A 20 percent chance of snow before 1pm. Mostly cloudy, then gradually becoming sunny, with a temperature falling to around 27 by 4pm. Blustery, with a northwest wind around 21 mph.

    High: 31 °F⇓

    Slight Chance
    Snow and
    Blustery

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 21. Blustery.

    Low: 21 °F

    Mostly Clear
    and Blustery
    then Partly
    Cloudy

  • Friday

    Friday: Increasing clouds, with a high near 32.

    High: 32 °F

    Increasing
    Clouds

  • Friday Night

    Friday Night: Partly cloudy, with a low around 26.

    Low: 26 °F

    Partly Cloudy

Detailed Forecast

This Afternoon
Mostly cloudy, with a high near 33. Wind chill values between 15 and 20. Windy, with a west wind around 30 mph.
Tonight
Mostly cloudy, with a low around 28. Wind chill values between 15 and 20. Windy, with a west wind 22 to 30 mph.
Wednesday
Partly sunny, with a high near 34. Wind chill values between 15 and 25. Southwest wind 15 to 18 mph.
Wednesday Night
Snow likely, mainly after 1am. Increasing clouds, with a steady temperature around 32. Wind chill values between 20 and 25. Southwest wind 15 to 18 mph. Chance of precipitation is 70%. New snow accumulation of less than one inch possible.
New Year's Day
A 20 percent chance of snow before 1pm. Mostly cloudy, then gradually becoming sunny, with a temperature falling to around 27 by 4pm. Blustery, with a northwest wind around 21 mph.
Thursday Night
Mostly clear, with a low around 21. Blustery.
Friday
Increasing clouds, with a high near 32.
Friday Night
Partly cloudy, with a low around 26.
Saturday
Mostly sunny, with a high near 31.
Saturday Night
Partly cloudy, with a low around 24.
Sunday
Mostly sunny, with a high near 32.
Sunday Night
Mostly cloudy, with a low around 27.
Monday
A chance of rain and snow. Mostly cloudy, with a high near 37. Chance of precipitation is 30%.
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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:
1:40 pm EST Dec 30, 2025
Forecast Valid:
1pm EST Dec 30, 2025-6pm EST Jan 5, 2026
 
Forecast Discussion
 
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Additional Resources

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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