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.

Light Rain Fog/Mist

48°F

9°C

Humidity 96%
Wind Speed S 6 mph
Barometer 29.77 in (1008.3 mb)
Dewpoint 47°F (8°C)
Visibility 1.50 mi
Wind Chill45°F (7°C)
Last update 30 Apr 6:56 am EDT
Extended Forecast for

Port Jefferson NY

  • Today

    Today: Showers, mainly before 8am. High near 60. Light and variable wind becoming north around 5 mph in the afternoon. Chance of precipitation is 80%.

    High: 60 °F

    Showers then
    Partly Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 45. Northwest wind 5 to 8 mph.

    Low: 45 °F

    Partly Cloudy

  • Friday

    Friday: Sunny, with a high near 63. West wind around 10 mph.

    High: 63 °F

    Sunny

  • Friday Night

    Friday Night: A 20 percent chance of showers after 2am. Mostly cloudy, with a low around 46. West wind 5 to 7 mph.

    Low: 46 °F

    Partly Cloudy
    then Slight
    Chance
    Showers

  • Saturday

    Saturday: A 40 percent chance of rain, mainly after 2pm. Mostly cloudy, with a high near 58. Light and variable wind becoming south 5 to 7 mph in the morning.

    High: 58 °F

    Chance Rain

  • Saturday Night

    Saturday Night: A 40 percent chance of rain. Mostly cloudy, with a low around 44.

    Low: 44 °F

    Chance Rain

  • Sunday

    Sunday: Mostly sunny, with a high near 59.

    High: 59 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 44.

    Low: 44 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 63.

    High: 63 °F

    Sunny

Detailed Forecast

Today
Showers, mainly before 8am. High near 60. Light and variable wind becoming north around 5 mph in the afternoon. Chance of precipitation is 80%.
Tonight
Partly cloudy, with a low around 45. Northwest wind 5 to 8 mph.
Friday
Sunny, with a high near 63. West wind around 10 mph.
Friday Night
A 20 percent chance of showers after 2am. Mostly cloudy, with a low around 46. West wind 5 to 7 mph.
Saturday
A 40 percent chance of rain, mainly after 2pm. Mostly cloudy, with a high near 58. Light and variable wind becoming south 5 to 7 mph in the morning.
Saturday Night
A 40 percent chance of rain. Mostly cloudy, with a low around 44.
Sunday
Mostly sunny, with a high near 59.
Sunday Night
Mostly clear, with a low around 44.
Monday
Sunny, with a high near 63.
Monday Night
Partly cloudy, with a low around 51.
Tuesday
Mostly sunny, with a high near 68.
Tuesday Night
Mostly cloudy, with a low around 52.
Wednesday
A 40 percent chance of showers. Partly sunny, with a high near 67.
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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:
4:33 am EDT Apr 30, 2026
Forecast Valid:
7am EDT Apr 30, 2026-6pm EDT May 6, 2026
 
Forecast Discussion
 
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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