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.

Mostly Cloudy

79°F

26°C

Humidity 79%
Wind Speed SW 8 mph
Barometer 29.86 in (1011.0 mb)
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Heat Index82°F (28°C)
Last update 18 Aug 3:56 pm EDT
Extended Forecast for

Setauket-East Setauket NY

  • This Afternoon

    This Afternoon: A 20 percent chance of showers before 5pm. Mostly sunny, with a high near 84. Southwest wind around 5 mph.

    High: 84 °F

    Slight Chance
    Showers

  • 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 30 percent chance of showers before 8pm. Mostly cloudy, with a low around 65.

    Low: 65 °F

    Chance
    Showers then
    Partly Cloudy

  • 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

Detailed Forecast

This Afternoon
A 20 percent chance of showers before 5pm. Mostly sunny, with a high near 84. Southwest wind around 5 mph.
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 30 percent chance of showers before 8pm. Mostly cloudy, with a low around 65.
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. 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:
4pm 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