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.

Light Drizzle Fog/Mist

69°F

21°C

Humidity 96%
Wind Speed SE 7 mph
Barometer 29.86 in (1011.1 mb)
Dewpoint 68°F (20°C)
Visibility 0.50 mi
Last update 18 Jun 10:56 pm EDT
Extended Forecast for

Port Jefferson NY

  • Tonight

    Tonight: A 20 percent chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 69. Southwest wind 3 to 5 mph.

    Low: 69 °F

    Slight Chance
    T-storms

  • Juneteenth

    Juneteenth: A chance of thunderstorms after 5pm. Mostly sunny, with a high near 88. Southwest wind 6 to 14 mph. Chance of precipitation is 30%.

    High: 88 °F

    Partly Sunny
    then Chance
    T-storms

  • Thursday Night

    Thursday Night: A 30 percent chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 69. Southwest wind 10 to 17 mph.

    Low: 69 °F

    Chance
    T-storms then
    Chance
    Showers

  • Friday

    Friday: Sunny, with a high near 83. West wind 10 to 13 mph.

    High: 83 °F

    Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 66. West wind 5 to 7 mph.

    Low: 66 °F

    Mostly Clear

  • Saturday

    Saturday: Mostly sunny, with a high near 84.

    High: 84 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around 68.

    Low: 68 °F

    Mostly Cloudy

  • Sunday

    Sunday: Partly sunny, with a high near 84.

    High: 84 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 69.

    Low: 69 °F

    Partly Cloudy

Detailed Forecast

Tonight
A 20 percent chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 69. Southwest wind 3 to 5 mph.
Juneteenth
A chance of thunderstorms after 5pm. Mostly sunny, with a high near 88. Southwest wind 6 to 14 mph. Chance of precipitation is 30%.
Thursday Night
A 30 percent chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 69. Southwest wind 10 to 17 mph.
Friday
Sunny, with a high near 83. West wind 10 to 13 mph.
Friday Night
Mostly clear, with a low around 66. West wind 5 to 7 mph.
Saturday
Mostly sunny, with a high near 84.
Saturday Night
Mostly cloudy, with a low around 68.
Sunday
Partly sunny, with a high near 84.
Sunday Night
Partly cloudy, with a low around 69.
Monday
Sunny, with a high near 88.
Monday Night
Mostly clear, with a low around 71.
Tuesday
Sunny, with a high near 91.
Tuesday Night
Mostly clear, with a low around 73.
Wednesday
Sunny, with a high near 88.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.93°N 73.06°W (Elev. 161 ft)
Last Update:
7:33 pm EDT Jun 18, 2025
Forecast Valid:
11pm EDT Jun 18, 2025-6pm EDT Jun 25, 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