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.

Fair

34°F

1°C

Humidity 61%
Wind Speed W 9 mph
Barometer 29.85 in (1010.7 mb)
Dewpoint 22°F (-6°C)
Visibility 10.00 mi
Wind Chill27°F (-3°C)
Last update 28 Nov 3:56 am EST
Extended Forecast for

Port Jefferson NY

  • Today

    Today: Mostly sunny, with a high near 43. Wind chill values between 20 and 30. Windy, with a west wind 17 to 26 mph, with gusts as high as 38 mph.

    High: 43 °F

    Mostly Sunny
    and Windy

  • Tonight

    Tonight: Mostly clear, with a low around 34. Wind chill values between 25 and 30. Breezy, with a west wind 16 to 24 mph, with gusts as high as 34 mph.

    Low: 34 °F

    Mostly Clear
    and Breezy

  • Saturday

    Saturday: Sunny, with a high near 42. Wind chill values between 25 and 35. West wind 7 to 15 mph.

    High: 42 °F

    Sunny

  • Saturday Night

    Saturday Night: Increasing clouds, with a low around 34. Calm wind becoming southeast around 6 mph after midnight.

    Low: 34 °F

    Increasing
    Clouds

  • Sunday

    Sunday: Showers, mainly after 1pm. High near 51. South wind 9 to 15 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 51 °F

    Chance
    Showers then
    Showers

  • Sunday Night

    Sunday Night: A chance of showers before 1am, then a chance of sprinkles after 1am. Cloudy, then gradually becoming partly cloudy, with a low around 36. Chance of precipitation is 50%.

    Low: 36 °F

    Chance
    Showers

  • Monday

    Monday: Mostly sunny, with a high near 42.

    High: 42 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 31.

    Low: 31 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: Rain likely, mainly after 1pm. Cloudy, with a high near 44. Chance of precipitation is 60%.

    High: 44 °F

    Rain Likely

Detailed Forecast

Today
Mostly sunny, with a high near 43. Wind chill values between 20 and 30. Windy, with a west wind 17 to 26 mph, with gusts as high as 38 mph.
Tonight
Mostly clear, with a low around 34. Wind chill values between 25 and 30. Breezy, with a west wind 16 to 24 mph, with gusts as high as 34 mph.
Saturday
Sunny, with a high near 42. Wind chill values between 25 and 35. West wind 7 to 15 mph.
Saturday Night
Increasing clouds, with a low around 34. Calm wind becoming southeast around 6 mph after midnight.
Sunday
Showers, mainly after 1pm. High near 51. South wind 9 to 15 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.
Sunday Night
A chance of showers before 1am, then a chance of sprinkles after 1am. Cloudy, then gradually becoming partly cloudy, with a low around 36. Chance of precipitation is 50%.
Monday
Mostly sunny, with a high near 42.
Monday Night
Mostly cloudy, with a low around 31.
Tuesday
Rain likely, mainly after 1pm. Cloudy, with a high near 44. Chance of precipitation is 60%.
Tuesday Night
A 50 percent chance of rain. Mostly cloudy, with a low around 32.
Wednesday
Mostly sunny, with a high near 40.
Wednesday Night
Partly cloudy, with a low around 31.
Thursday
Mostly cloudy, with a high near 42.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.95°N 73.05°W (Elev. 151 ft)
Last Update:
1:12 am EST Nov 28, 2025
Forecast Valid:
4am EST Nov 28, 2025-6pm EST Dec 4, 2025
 
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Additional Resources

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Chance of Precipitation