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.

Fog/Mist

73°F

23°C

Humidity 100%
Wind Speed S 3 mph
Barometer 29.96 in (1014.6 mb)
Dewpoint 73°F (23°C)
Visibility 4.00 mi
Last update 28 Aug 2:56 am EDT
Extended Forecast for

Port Jefferson NYSimilar City Names

  • Overnight

    Overnight: Patchy fog. Otherwise, mostly cloudy, with a low around 70. Light south wind.

    Low: 70 °F

    Patchy Fog

  • Friday

    Friday: A slight chance of showers between 11am and 2pm, then a chance of showers and thunderstorms after 2pm. Areas of fog before 8am. Otherwise, mostly cloudy, with a high near 81. Calm wind becoming west around 5 mph in the afternoon. Chance of precipitation is 40%.

    High: 81 °F

    Slight Chance
    Showers and
    Areas Fog
    then Chance
    T-storms

  • Friday Night

    Friday Night: A 30 percent chance of showers and thunderstorms before 8pm. Mostly cloudy, with a low around 64. West wind 5 to 10 mph becoming north after midnight.

    Low: 64 °F

    Chance
    T-storms then
    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 77. North wind 5 to 9 mph becoming calm in the afternoon.

    High: 77 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 65. Light south wind.

    Low: 65 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 81.

    High: 81 °F

    Sunny

  • Sunday Night

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

    Low: 69 °F

    Mostly Cloudy

  • Monday

    Monday: Partly sunny, with a high near 81.

    High: 81 °F

    Partly Sunny

  • Monday Night

    Monday Night: A 30 percent chance of showers after 2am. Mostly cloudy, with a low around 69.

    Low: 69 °F

    Mostly Cloudy
    then Chance
    Showers

Detailed Forecast

Overnight
Patchy fog. Otherwise, mostly cloudy, with a low around 70. Light south wind.
Friday
A slight chance of showers between 11am and 2pm, then a chance of showers and thunderstorms after 2pm. Areas of fog before 8am. Otherwise, mostly cloudy, with a high near 81. Calm wind becoming west around 5 mph in the afternoon. Chance of precipitation is 40%.
Friday Night
A 30 percent chance of showers and thunderstorms before 8pm. Mostly cloudy, with a low around 64. West wind 5 to 10 mph becoming north after midnight.
Saturday
Mostly sunny, with a high near 77. North wind 5 to 9 mph becoming calm in the afternoon.
Saturday Night
Mostly clear, with a low around 65. Light south wind.
Sunday
Sunny, with a high near 81.
Sunday Night
Mostly cloudy, with a low around 69.
Monday
Partly sunny, with a high near 81.
Monday Night
A 30 percent chance of showers after 2am. Mostly cloudy, with a low around 69.
Tuesday
A 50 percent chance of showers. Mostly cloudy, with a high near 79.
Tuesday Night
A 50 percent chance of showers. Mostly cloudy, with a low around 69.
Wednesday
A 50 percent chance of showers. Partly sunny, with a high near 79.
Wednesday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 69.
Thursday
Partly sunny, with a high near 80.
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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:
3:26 am EDT Aug 28, 2026
Forecast Valid:
3am EDT Aug 28, 2026-6pm EDT Sep 3, 2026
 
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Additional Resources

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Chance of Precipitation