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.

Overcast

73°F

23°C

Humidity 84%
Wind Speed SE 5 mph
Barometer 30.09 in (1018.8 mb)
Dewpoint 68°F (20°C)
Visibility 10.00 mi
Last update 12 Jul 7:56 pm EDT
Extended Forecast for

Stony Brook NY

  • Tonight

    Tonight: Mostly cloudy, with a low around 70. East wind 3 to 6 mph.

    Low: 70 °F

    Mostly Cloudy

  • Sunday

    Sunday: Partly sunny, with a high near 85. East wind 5 to 8 mph.

    High: 85 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Mostly cloudy, with a low around 71. Southeast wind 3 to 6 mph.

    Low: 71 °F

    Mostly Cloudy

  • Monday

    Monday: A 40 percent chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 86. South wind 3 to 6 mph.

    High: 86 °F

    Mostly Cloudy
    then Chance
    T-storms

  • Monday Night

    Monday Night: A chance of showers and thunderstorms before 2am, then a slight chance of showers. Mostly cloudy, with a low around 72. South wind 3 to 6 mph. Chance of precipitation is 30%.

    Low: 72 °F

    Chance
    T-storms then
    Chance
    Showers

  • Tuesday

    Tuesday: Sunny, with a high near 92.

    High: 92 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 74.

    Low: 74 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 91.

    High: 91 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 75.

    Low: 75 °F

    Partly Cloudy

Detailed Forecast

Tonight
Mostly cloudy, with a low around 70. East wind 3 to 6 mph.
Sunday
Partly sunny, with a high near 85. East wind 5 to 8 mph.
Sunday Night
Mostly cloudy, with a low around 71. Southeast wind 3 to 6 mph.
Monday
A 40 percent chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 86. South wind 3 to 6 mph.
Monday Night
A chance of showers and thunderstorms before 2am, then a slight chance of showers. Mostly cloudy, with a low around 72. South wind 3 to 6 mph. Chance of precipitation is 30%.
Tuesday
Sunny, with a high near 92.
Tuesday Night
Mostly clear, with a low around 74.
Wednesday
Sunny, with a high near 91.
Wednesday Night
Partly cloudy, with a low around 75.
Thursday
A 30 percent chance of showers after 2pm. Partly sunny, with a high near 91.
Thursday Night
A 30 percent chance of showers. Mostly cloudy, with a low around 75.
Friday
A 40 percent chance of showers and thunderstorms. Partly sunny, with a high near 90.
Friday Night
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 72.
Saturday
A 30 percent chance of showers. Partly sunny, with a high near 87.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.92°N 73.12°W (Elev. 112 ft)
Last Update:
6:14 pm EDT Jul 12, 2025
Forecast Valid:
8pm EDT Jul 12, 2025-6pm EDT Jul 19, 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