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.

Partly Cloudy

76°F

24°C

Humidity 85%
Wind Speed S 8 mph
Barometer 29.87 in (1011.3 mb)
Dewpoint 71°F (22°C)
Visibility 10.00 mi
Heat Index77°F (25°C)
Last update 18 Aug 6:56 pm EDT
Extended Forecast for

Setauket-East Setauket NY

  • Tonight

    Tonight: Increasing clouds, with a low around 68. South wind around 5 mph becoming calm in the evening.

    Low: 68 °F

    Increasing
    Clouds

  • Wednesday

    Wednesday: Partly sunny, then gradually becoming sunny, with a high near 85. Calm wind becoming west around 6 mph in the afternoon.

    High: 85 °F

    Becoming
    Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 70. South wind 3 to 6 mph.

    Low: 70 °F

    Partly Cloudy

  • Thursday

    Thursday: A 30 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 83. Northwest wind 3 to 5 mph.

    High: 83 °F

    Mostly Sunny
    then Chance
    Showers

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms before 8pm, then a slight chance of showers between 8pm and 2am. Mostly cloudy, with a low around 65. Calm wind becoming north around 5 mph after midnight. Chance of precipitation is 30%.

    Low: 65 °F

    Chance
    Showers

  • Friday

    Friday: Mostly sunny, with a high near 81.

    High: 81 °F

    Mostly Sunny

  • Friday Night

    Friday Night: A 30 percent chance of showers after 2am. Mostly cloudy, with a low around 65.

    Low: 65 °F

    Mostly Cloudy
    then Chance
    Showers

  • Saturday

    Saturday: A 50 percent chance of showers. Partly sunny, with a high near 78.

    High: 78 °F

    Chance
    Showers

  • Saturday Night

    Saturday Night: Showers likely, mainly after 2am. Mostly cloudy, with a low around 66. Chance of precipitation is 60%.

    Low: 66 °F

    Showers
    Likely

Detailed Forecast

Tonight
Increasing clouds, with a low around 68. South wind around 5 mph becoming calm in the evening.
Wednesday
Partly sunny, then gradually becoming sunny, with a high near 85. Calm wind becoming west around 6 mph in the afternoon.
Wednesday Night
Partly cloudy, with a low around 70. South wind 3 to 6 mph.
Thursday
A 30 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 83. Northwest wind 3 to 5 mph.
Thursday Night
A chance of showers and thunderstorms before 8pm, then a slight chance of showers between 8pm and 2am. Mostly cloudy, with a low around 65. Calm wind becoming north around 5 mph after midnight. Chance of precipitation is 30%.
Friday
Mostly sunny, with a high near 81.
Friday Night
A 30 percent chance of showers after 2am. Mostly cloudy, with a low around 65.
Saturday
A 50 percent chance of showers. Partly sunny, with a high near 78.
Saturday Night
Showers likely, mainly after 2am. Mostly cloudy, with a low around 66. Chance of precipitation is 60%.
Sunday
Showers likely, mainly before 8am. Partly sunny, with a high near 81. Chance of precipitation is 60%.
Sunday Night
A 30 percent chance of showers. Partly cloudy, with a low around 65.
Monday
Sunny, with a high near 81.
Monday Night
Mostly clear, with a low around 64.
Tuesday
Sunny, with a high near 81.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Setauket-East Setauket NY
 40.92°N 73.12°W (Elev. 112 ft)
Last Update:
2:34 pm EDT Aug 18, 2026
Forecast Valid:
7pm EDT Aug 18, 2026-6pm EDT Aug 25, 2026
 
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