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.

Fog/Mist

43°F

6°C

Humidity 97%
Wind Speed S 7 mph
Barometer 30.17 in (1021.8 mb)
Dewpoint 42°F (6°C)
Visibility 1.50 mi
Wind Chill39°F (4°C)
Last update 7 Mar 11:56 am EST
Extended Forecast for

Port Jefferson NY

  • This Afternoon

    This Afternoon: Areas of drizzle before 1pm. Patchy fog. Otherwise, cloudy, with a high near 45. South wind around 8 mph.

    High: 45 °F

    Areas Drizzle
    and Patchy
    Fog

  • Tonight

    Tonight: A 50 percent chance of showers after 10pm. Areas of fog before 1am. Otherwise, cloudy, with a temperature rising to around 49 by 5am. Southwest wind 9 to 13 mph.

    Low: 43 °F⇑

    Chance
    Showers and
    Areas Fog

  • Sunday

    Sunday: A 40 percent chance of rain, mainly before 1pm. Mostly cloudy, with a high near 55. Southwest wind 10 to 13 mph.

    High: 55 °F

    Chance Rain

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 39. West wind 6 to 9 mph.

    Low: 39 °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 43.

    Low: 43 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 56.

    High: 56 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 43.

    Low: 43 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: A 40 percent chance of rain. Cloudy, with a high near 53.

    High: 53 °F

    Chance Rain

Detailed Forecast

This Afternoon
Areas of drizzle before 1pm. Patchy fog. Otherwise, cloudy, with a high near 45. South wind around 8 mph.
Tonight
A 50 percent chance of showers after 10pm. Areas of fog before 1am. Otherwise, cloudy, with a temperature rising to around 49 by 5am. Southwest wind 9 to 13 mph.
Sunday
A 40 percent chance of rain, mainly before 1pm. Mostly cloudy, with a high near 55. Southwest wind 10 to 13 mph.
Sunday Night
Mostly clear, with a low around 39. West wind 6 to 9 mph.
Monday
Sunny, with a high near 53. Southwest wind 6 to 13 mph.
Monday Night
Partly cloudy, with a low around 43.
Tuesday
Mostly sunny, with a high near 56.
Tuesday Night
Mostly cloudy, with a low around 43.
Wednesday
A 40 percent chance of rain. Cloudy, with a high near 53.
Wednesday Night
Rain likely, mainly after 1am. Cloudy, with a low around 45. Breezy. Chance of precipitation is 60%.
Thursday
A 50 percent chance of rain. Mostly cloudy, with a high near 50. Breezy.
Thursday Night
Partly cloudy, with a low around 32. Breezy.
Friday
Partly sunny, with a high near 41.
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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:
11:59 am EST Mar 7, 2026
Forecast Valid:
12pm EST Mar 7, 2026-6pm EDT Mar 13, 2026
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

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