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.

Overcast

36°F

2°C

Humidity 86%
Wind Speed NW 3 mph
Barometer 29.93 in (1013.6 mb)
Dewpoint 32°F (0°C)
Visibility 10.00 mi
Last update 6 Dec 2:56 am EST
Extended Forecast for

Port Jefferson NY

  • Overnight

    Overnight: A chance of drizzle. Cloudy, with a steady temperature around 35. Light northeast wind.

    Low: 35 °F

    Chance
    Drizzle

  • Saturday

    Saturday: A chance of drizzle before 10am. Mostly cloudy, with a high near 41. Light and variable wind becoming west 5 to 7 mph in the morning.

    High: 41 °F

    Chance
    Drizzle then
    Mostly Cloudy

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 31. West wind 6 to 9 mph.

    Low: 31 °F

    Partly Cloudy

  • Sunday

    Sunday: Partly sunny, with a high near 40. North wind around 6 mph becoming southwest in the afternoon.

    High: 40 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Mostly cloudy, with a low around 26. Southwest wind 6 to 11 mph becoming northwest 13 to 18 mph after midnight.

    Low: 26 °F

    Mostly Cloudy

  • Monday

    Monday: Mostly sunny, with a high near 32. Breezy.

    High: 32 °F

    Mostly Sunny
    and Breezy
    then Mostly
    Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 20.

    Low: 20 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Partly sunny, with a high near 39.

    High: 39 °F

    Partly Sunny

  • Tuesday Night

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

    Low: 33 °F

    Mostly Cloudy

Detailed Forecast

Overnight
A chance of drizzle. Cloudy, with a steady temperature around 35. Light northeast wind.
Saturday
A chance of drizzle before 10am. Mostly cloudy, with a high near 41. Light and variable wind becoming west 5 to 7 mph in the morning.
Saturday Night
Partly cloudy, with a low around 31. West wind 6 to 9 mph.
Sunday
Partly sunny, with a high near 40. North wind around 6 mph becoming southwest in the afternoon.
Sunday Night
Mostly cloudy, with a low around 26. Southwest wind 6 to 11 mph becoming northwest 13 to 18 mph after midnight.
Monday
Mostly sunny, with a high near 32. Breezy.
Monday Night
Partly cloudy, with a low around 20.
Tuesday
Partly sunny, with a high near 39.
Tuesday Night
Mostly cloudy, with a low around 33.
Wednesday
A 30 percent chance of rain after 1pm. Mostly cloudy, with a high near 47.
Wednesday Night
A 50 percent chance of rain. Mostly cloudy, with a low around 36.
Thursday
A 30 percent chance of rain. Partly sunny, with a high near 42.
Thursday Night
A 30 percent chance of rain. Mostly cloudy, with a low around 29.
Friday
A chance of rain and snow. Partly sunny, with a high near 37. Chance of precipitation is 30%.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.95°N 73.05°W (Elev. 151 ft)
Last Update:
12:53 am EST Dec 6, 2025
Forecast Valid:
3am EST Dec 6, 2025-6pm EST Dec 12, 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

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation