Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

Fair

34°F

1°C

Humidity 73%
Wind Speed W 5 mph
Barometer 29.94 in (1014.0 mb)
Dewpoint 26°F (-3°C)
Visibility 10.00 mi
Wind Chill29°F (-2°C)
Last update 6 Dec 9:56 pm EST
Extended Forecast for

Port Jefferson NY

  • Tonight

    Tonight: Mostly clear, with a low around 31. Northwest wind 6 to 9 mph.

    Low: 31 °F

    Mostly Clear

  • Sunday

    Sunday: Partly sunny, with a high near 41. North wind around 6 mph becoming south in the afternoon.

    High: 41 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 25. Wind chill values between 15 and 20. Southwest wind 7 to 15 mph becoming northwest after midnight.

    Low: 25 °F

    Partly Cloudy

  • Monday

    Monday: Mostly sunny, with a high near 31. Wind chill values between 15 and 20. North wind 14 to 17 mph.

    High: 31 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 19. North wind 6 to 13 mph.

    Low: 19 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Increasing clouds, with a high near 39.

    High: 39 °F

    Increasing
    Clouds

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 33.

    Low: 33 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: A 40 percent chance of rain.  Mostly cloudy, with a high near 47.

    High: 47 °F

    Chance Rain

  • Wednesday Night

    Wednesday Night: A 40 percent chance of rain.  Mostly cloudy, with a low around 36.

    Low: 36 °F

    Chance Rain

Detailed Forecast

Tonight
Mostly clear, with a low around 31. Northwest wind 6 to 9 mph.
Sunday
Partly sunny, with a high near 41. North wind around 6 mph becoming south in the afternoon.
Sunday Night
Partly cloudy, with a low around 25. Wind chill values between 15 and 20. Southwest wind 7 to 15 mph becoming northwest after midnight.
Monday
Mostly sunny, with a high near 31. Wind chill values between 15 and 20. North wind 14 to 17 mph.
Monday Night
Partly cloudy, with a low around 19. North wind 6 to 13 mph.
Tuesday
Increasing clouds, with a high near 39.
Tuesday Night
Mostly cloudy, with a low around 33.
Wednesday
A 40 percent chance of rain. Mostly cloudy, with a high near 47.
Wednesday Night
A 40 percent chance of rain. Mostly cloudy, with a low around 36.
Thursday
A 30 percent chance of rain before 1pm. Partly sunny, with a high near 43.
Thursday Night
A 40 percent chance of rain. Mostly cloudy, with a low around 31.
Friday
A 30 percent chance of rain. Partly sunny, with a high near 40.
Friday Night
A 30 percent chance of snow. Partly cloudy, with a low around 25.
Saturday
Mostly sunny, with a high near 34.
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ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.95°N 73.05°W (Elev. 151 ft)
4:40 pm EST Dec 6, 2025
10pm EST Dec 6, 2025-6pm EST Dec 13, 2025
 
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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