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 Drizzle Fog

42°F

6°C

Humidity 100%
Wind Speed S 7 mph
Barometer 29.90 in (1012.7 mb)
Dewpoint 42°F (6°C)
Visibility 0.25 mi
Wind Chill38°F (3°C)
Last update 7 Mar 11:56 pm EDT
Extended Forecast for

Port Jefferson NY

Dense Fog Advisory until March 8, 09:00am
Click here for hazard details and duration
Dense Fog Advisory
  •  
    Dense Fog Advisory until March 8, 09:00am

    NOW until 9:00am Sun

    Dense Fog Advisory

  • Tonight

    Low: 43 °F⇑

    Showers
    Likely and
    Areas Dense
    Fog

  • Sunday

    Sunday: Showers likely, mainly before 7am. Patchy fog before 10am. Otherwise, mostly cloudy, with a high near 55. Southwest wind 11 to 14 mph. Chance of precipitation is 60%.

    High: 55 °F

    Showers
    Likely and
    Patchy Fog
    then Chance
    Showers

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 41. West wind 6 to 10 mph.

    Low: 41 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 53. Southwest wind 6 to 13 mph.

    High: 53 °F

    Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 40. South wind 6 to 10 mph.

    Low: 40 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 55.

    High: 55 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Increasing clouds, with a low around 44.

    Low: 44 °F

    Increasing
    Clouds

  • Wednesday

    Wednesday: Cloudy, with a high near 52.

    High: 52 °F

    Cloudy

Detailed Forecast

Tonight
Patchy drizzle with a chance of showers before 4am, then showers likely with areas of drizzle after 4am. The drizzle could be heavy at times. Areas of dense fog. Otherwise, cloudy, with a temperature rising to around 47 by 5am. South wind 11 to 13 mph. Chance of precipitation is 70%.
Sunday
Showers likely, mainly before 7am. Patchy fog before 10am. Otherwise, mostly cloudy, with a high near 55. Southwest wind 11 to 14 mph. Chance of precipitation is 60%.
Sunday Night
Mostly clear, with a low around 41. West wind 6 to 10 mph.
Monday
Sunny, with a high near 53. Southwest wind 6 to 13 mph.
Monday Night
Partly cloudy, with a low around 40. South wind 6 to 10 mph.
Tuesday
Mostly sunny, with a high near 55.
Tuesday Night
Increasing clouds, with a low around 44.
Wednesday
Cloudy, with a high near 52.
Wednesday Night
A 40 percent chance of showers after 1am. Cloudy, with a low around 47. Breezy.
Thursday
Showers likely, mainly before 1pm. Mostly cloudy, with a high near 53. Breezy. Chance of precipitation is 60%.
Thursday Night
A chance of rain and snow showers. Partly cloudy, with a low around 32. Breezy. Chance of precipitation is 30%.
Friday
Mostly sunny, with a high near 41.
Friday Night
A 30 percent chance of rain. Mostly cloudy, with a low around 37. Breezy.
Saturday
Mostly cloudy, with a high near 47.
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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:
3:40 pm EST Mar 7, 2026
Forecast Valid:
11pm EST Mar 7, 2026-6pm EDT Mar 14, 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