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.

Light Snow Fog/Mist

33°F

1°C

Humidity 92%
Wind Speed N 14 mph
Barometer 29.78 in (1008.5 mb)
Dewpoint 31°F (-1°C)
Visibility 2.00 mi
Wind Chill23°F (-5°C)
Last update 18 Jan 9:56 pm EST
Extended Forecast for

Port Jefferson NY

Winter Weather Advisory January 18, 10:53pm until January 19, 04:00am
Click here for hazard details and duration
Winter Weather Advisory
  •  
    Winter Weather Advisory January 18, 10:53pm until January 19, 04:00am

    NOW until 4:00am Mon

    Winter Weather Advisory

  • Tonight

    Low: 25 °F

    Snow Likely

  • M.L.King Day

    M.L.King Day: Mostly cloudy, then gradually becoming sunny, with a high near 32. Wind chill values between 15 and 20. Southwest wind 9 to 15 mph.

    High: 32 °F

    Decreasing
    Clouds

  • Monday Night

    Monday Night: Mostly cloudy, then gradually becoming clear, with a low around 16. Wind chill values between 5 and 15. Breezy, with a west wind 14 to 20 mph.

    Low: 16 °F

    Decreasing
    Clouds and
    Breezy

  • Tuesday

    Tuesday: Sunny, with a high near 24. Wind chill values between zero and 10. West wind around 17 mph, with gusts as high as 29 mph.

    High: 24 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Clear, with a low around 13. West wind 8 to 13 mph.

    Low: 13 °F

    Clear

  • Wednesday

    Wednesday: Mostly sunny, with a high near 36.

    High: 36 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 28.

    Low: 28 °F

    Mostly Cloudy

  • Thursday

    Thursday: A 30 percent chance of rain before 1pm. Partly sunny, with a high near 39.

    High: 39 °F

    Chance Rain

Detailed Forecast

Tonight
Snow likely, mainly before 1am. Cloudy, with a low around 25. Northwest wind 6 to 10 mph. Chance of precipitation is 70%. Total nighttime snow accumulation of 2 to 4 inches possible.
M.L.King Day
Mostly cloudy, then gradually becoming sunny, with a high near 32. Wind chill values between 15 and 20. Southwest wind 9 to 15 mph.
Monday Night
Mostly cloudy, then gradually becoming clear, with a low around 16. Wind chill values between 5 and 15. Breezy, with a west wind 14 to 20 mph.
Tuesday
Sunny, with a high near 24. Wind chill values between zero and 10. West wind around 17 mph, with gusts as high as 29 mph.
Tuesday Night
Clear, with a low around 13. West wind 8 to 13 mph.
Wednesday
Mostly sunny, with a high near 36.
Wednesday Night
Mostly cloudy, with a low around 28.
Thursday
A 30 percent chance of rain before 1pm. Partly sunny, with a high near 39.
Thursday Night
Mostly clear, with a low around 20.
Friday
Mostly sunny, with a high near 30.
Friday Night
Mostly cloudy, with a low around 18.
Saturday
A 30 percent chance of snow. Partly sunny, with a high near 29.
Saturday Night
A 30 percent chance of snow. Mostly cloudy, with a low around 12.
Sunday
A 30 percent chance of snow. Partly sunny, with a high near 23.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.93°N 73.06°W (Elev. 161 ft)
Last Update:
8:25 pm EST Jan 18, 2026
Forecast Valid:
10pm EST Jan 18, 2026-6pm EST Jan 25, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

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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