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.

Overcast

50°F

10°C

Humidity 54%
Wind Speed W 9 G 22 mph
Barometer 29.77 in (1008.2 mb)
Dewpoint 34°F (1°C)
Visibility 10.00 mi
Wind Chill46°F (8°C)
Last update 12 Nov 9:56 pm EST
Extended Forecast for

Port Jefferson NY

  • Tonight

    Tonight: Partly cloudy, with a low around 45. West wind around 17 mph.

    Low: 45 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 50. West wind 15 to 17 mph, with gusts as high as 29 mph.

    High: 50 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 39. Northwest wind 14 to 17 mph.

    Low: 39 °F

    Mostly Clear

  • Friday

    Friday: Mostly sunny, with a high near 49. Northwest wind around 15 mph.

    High: 49 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 35. Northwest wind 11 to 14 mph.

    Low: 35 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 50.

    High: 50 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Rain likely, mainly after 1am. Mostly cloudy, with a low around 42. Chance of precipitation is 70%.

    Low: 42 °F

    Chance Rain
    then Rain
    Likely

  • Sunday

    Sunday: Rain likely, mainly before 1pm. Mostly cloudy, with a high near 57. Breezy. Chance of precipitation is 70%.

    High: 57 °F

    Rain Likely
    and Breezy

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 38. Breezy.

    Low: 38 °F

    Partly Cloudy
    and Breezy
    then Partly
    Cloudy

Detailed Forecast

Tonight
Partly cloudy, with a low around 45. West wind around 17 mph.
Thursday
Mostly sunny, with a high near 50. West wind 15 to 17 mph, with gusts as high as 29 mph.
Thursday Night
Mostly clear, with a low around 39. Northwest wind 14 to 17 mph.
Friday
Mostly sunny, with a high near 49. Northwest wind around 15 mph.
Friday Night
Partly cloudy, with a low around 35. Northwest wind 11 to 14 mph.
Saturday
Mostly sunny, with a high near 50.
Saturday Night
Rain likely, mainly after 1am. Mostly cloudy, with a low around 42. Chance of precipitation is 70%.
Sunday
Rain likely, mainly before 1pm. Mostly cloudy, with a high near 57. Breezy. Chance of precipitation is 70%.
Sunday Night
Partly cloudy, with a low around 38. Breezy.
Monday
Mostly sunny, with a high near 48.
Monday Night
Partly cloudy, with a low around 37.
Tuesday
Partly sunny, with a high near 48.
Tuesday Night
Mostly cloudy, with a low around 38.
Wednesday
Mostly sunny, with a high near 50.
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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:
9:13 pm EST Nov 12, 2025
Forecast Valid:
10pm EST Nov 12, 2025-6pm EST Nov 19, 2025
 
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