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.

Rain Fog/Mist

46°F

8°C

Humidity 93%
Wind Speed N 8 mph
Barometer 29.78 in (1008.3 mb)
Dewpoint 44°F (7°C)
Visibility 2.00 mi
Wind Chill42°F (6°C)
Last update 2 Dec 12:56 pm EST
Extended Forecast for

Port Jefferson NY

  • This Afternoon

    This Afternoon: Rain. High near 46. Northeast wind 9 to 15 mph. Chance of precipitation is 100%. New precipitation amounts between a half and three quarters of an inch possible.

    High: 46 °F

    Rain

  • Tonight

    Tonight: Rain, mainly before 10pm. Low around 32. Northwest wind around 15 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

    Low: 32 °F

    Rain then
    Mostly Cloudy

  • Wednesday

    Wednesday: Sunny, with a high near 40. Wind chill values between 25 and 35. Northwest wind 6 to 11 mph.

    High: 40 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 32. Wind chill values between 25 and 30. West wind 6 to 11 mph.

    Low: 32 °F

    Partly Cloudy

  • Thursday

    Thursday: Partly sunny, with a high near 41. West wind 11 to 18 mph, with gusts as high as 30 mph.

    High: 41 °F

    Partly Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 19. Blustery.

    Low: 19 °F

    Mostly Clear
    and Blustery
    then Mostly
    Clear

  • Friday

    Friday: Increasing clouds, with a high near 35.

    High: 35 °F

    Increasing
    Clouds

  • Friday Night

    Friday Night: A chance of rain and snow before 1am, then a chance of snow. Mostly cloudy, with a low around 28. Chance of precipitation is 40%.

    Low: 28 °F

    Chance
    Rain/Snow

  • Saturday

    Saturday: A 30 percent chance of rain before 1pm. Partly sunny, with a high near 41.

    High: 41 °F

    Chance Rain

Detailed Forecast

This Afternoon
Rain. High near 46. Northeast wind 9 to 15 mph. Chance of precipitation is 100%. New precipitation amounts between a half and three quarters of an inch possible.
Tonight
Rain, mainly before 10pm. Low around 32. Northwest wind around 15 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.
Wednesday
Sunny, with a high near 40. Wind chill values between 25 and 35. Northwest wind 6 to 11 mph.
Wednesday Night
Partly cloudy, with a low around 32. Wind chill values between 25 and 30. West wind 6 to 11 mph.
Thursday
Partly sunny, with a high near 41. West wind 11 to 18 mph, with gusts as high as 30 mph.
Thursday Night
Mostly clear, with a low around 19. Blustery.
Friday
Increasing clouds, with a high near 35.
Friday Night
A chance of rain and snow before 1am, then a chance of snow. Mostly cloudy, with a low around 28. Chance of precipitation is 40%.
Saturday
A 30 percent chance of rain before 1pm. Partly sunny, with a high near 41.
Saturday Night
Partly cloudy, with a low around 31.
Sunday
Partly sunny, with a high near 38.
Sunday Night
Mostly cloudy, with a low around 23.
Monday
Partly sunny, with a high near 32.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.95°N 73.05°W (Elev. 151 ft)
Last Update:
1:01 pm EST Dec 2, 2025
Forecast Valid:
1pm EST Dec 2, 2025-6pm EST Dec 8, 2025
 
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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