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.

A Few Clouds

65°F

18°C

Humidity 90%
Wind Speed SW 13 mph
Barometer 29.83 in (1010.0 mb)
Dewpoint 62°F (17°C)
Visibility 10.00 mi
Last update 14 Oct 6:56 am EDT
Extended Forecast for

Port Jefferson NYSimilar City Names

  • Today

    Today: Increasing clouds, with a high near 76. West wind around 11 mph.

    High: 76 °F

    Increasing
    Clouds

  • Tonight

    Tonight: Partly cloudy, with a low around 54. North wind 9 to 13 mph.

    Low: 54 °F

    Partly Cloudy

  • Thursday

    Thursday: Sunny, with a steady temperature around 58. North wind 5 to 11 mph.

    High: 58 °F

    Sunny

  • Thursday Night

    Thursday Night: Showers after 2am. Low around 53. Southeast wind 5 to 8 mph. Chance of precipitation is 80%.

    Low: 53 °F

    Mostly Clear
    then Showers

  • Friday

    Friday: Showers, with thunderstorms also possible after 5pm. High near 70. Southwest wind 11 to 14 mph. Chance of precipitation is 100%. New rainfall amounts between a quarter and half of an inch possible.

    High: 70 °F

    Showers

  • Friday Night

    Friday Night: Showers likely before 2am. Cloudy, then gradually becoming partly cloudy, with a low around 46. Breezy. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

    Low: 46 °F

    Showers
    Likely and
    Breezy

  • Saturday

    Saturday: Sunny, with a high near 53. Breezy.

    High: 53 °F

    Sunny and
    Breezy

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 43.

    Low: 43 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 58.

    High: 58 °F

    Sunny

Detailed Forecast

Today
Increasing clouds, with a high near 76. West wind around 11 mph.
Tonight
Partly cloudy, with a low around 54. North wind 9 to 13 mph.
Thursday
Sunny, with a steady temperature around 58. North wind 5 to 11 mph.
Thursday Night
Showers after 2am. Low around 53. Southeast wind 5 to 8 mph. Chance of precipitation is 80%.
Friday
Showers, with thunderstorms also possible after 5pm. High near 70. Southwest wind 11 to 14 mph. Chance of precipitation is 100%. New rainfall amounts between a quarter and half of an inch possible.
Friday Night
Showers likely before 2am. Cloudy, then gradually becoming partly cloudy, with a low around 46. Breezy. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.
Saturday
Sunny, with a high near 53. Breezy.
Saturday Night
Mostly clear, with a low around 43.
Sunday
Sunny, with a high near 58.
Sunday Night
Mostly clear, with a low around 49.
Monday
Sunny, with a high near 62.
Monday Night
Partly cloudy, with a low around 53.
Tuesday
Partly sunny, with a high near 65.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NYSimilar City Names
 40.95°N 73.05°W (Elev. 151 ft)
Last Update:
7:09 am EDT Oct 14, 2026
Forecast Valid:
7am EDT Oct 14, 2026-6pm EDT Oct 20, 2026
 
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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