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.

Mostly Cloudy

57°F

14°C

Humidity 72%
Wind Speed SE 6 mph
Barometer 30.16 in (1021.4 mb)
Dewpoint 48°F (9°C)
Visibility 10.00 mi
Last update 15 Oct 9:56 pm EDT
Extended Forecast for

Port Jefferson NY

  • Tonight

    Tonight: Showers likely after 5am. Increasing clouds, with a temperature rising to around 60 by 5am. Southeast wind 8 to 10 mph. Chance of precipitation is 60%.

    Low: 57 °F⇑

    Partly Cloudy
    then Showers
    Likely

  • Friday

    Friday: Showers, with thunderstorms also possible after 2pm. High near 71. Southwest wind around 16 mph. Chance of precipitation is 90%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 71 °F

    Showers then
    Chance
    Showers

  • Friday Night

    Friday Night: Showers and thunderstorms before 2am, then showers likely. Low around 50. Breezy, with a west wind 14 to 22 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    Low: 50 °F

    Showers then
    Showers
    Likely and
    Breezy

  • Saturday

    Saturday: Showers likely before 8am. Cloudy through mid morning, then gradual clearing, with a high near 53. Windy, with a north wind 20 to 26 mph. Chance of precipitation is 60%.

    High: 53 °F

    Showers
    Likely and
    Windy then
    Mostly Sunny
    and Breezy

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 44. Breezy, with a north wind 17 to 22 mph.

    Low: 44 °F

    Mostly Clear
    and Breezy

  • Sunday

    Sunday: Sunny, with a high near 56.

    High: 56 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 48.

    Low: 48 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 61.

    High: 61 °F

    Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 51.

    Low: 51 °F

    Partly Cloudy

Detailed Forecast

Tonight
Showers likely after 5am. Increasing clouds, with a temperature rising to around 60 by 5am. Southeast wind 8 to 10 mph. Chance of precipitation is 60%.
Friday
Showers, with thunderstorms also possible after 2pm. High near 71. Southwest wind around 16 mph. Chance of precipitation is 90%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Friday Night
Showers and thunderstorms before 2am, then showers likely. Low around 50. Breezy, with a west wind 14 to 22 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Saturday
Showers likely before 8am. Cloudy through mid morning, then gradual clearing, with a high near 53. Windy, with a north wind 20 to 26 mph. Chance of precipitation is 60%.
Saturday Night
Mostly clear, with a low around 44. Breezy, with a north wind 17 to 22 mph.
Sunday
Sunny, with a high near 56.
Sunday Night
Mostly clear, with a low around 48.
Monday
Sunny, with a high near 61.
Monday Night
Partly cloudy, with a low around 51.
Tuesday
Mostly sunny, with a high near 63.
Tuesday Night
Partly cloudy, with a low around 53.
Wednesday
Sunny, with a high near 63.
Wednesday Night
Mostly clear, with a low around 51.
Thursday
Mostly sunny, with a high near 60.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.96°N 73.08°W (Elev. 3 ft)
Last Update:
2:36 pm EDT Oct 15, 2026
Forecast Valid:
10pm EDT Oct 15, 2026-6pm EDT Oct 22, 2026
 
Forecast Discussion
 
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Additional Resources

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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