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.

Fair

31°F

-1°C

Humidity 82%
Wind Speed Calm
Barometer 30.04 in (1017.2 mb)
Dewpoint 26°F (-3°C)
Visibility 10.00 mi
Last update 7 Dec 2:56 am EST
Extended Forecast for

Stony Brook NY

  • Overnight

    Overnight: Partly cloudy, with a low around 30. Northwest wind 3 to 5 mph.

    Low: 30 °F

    Partly Cloudy

  • Sunday

    Sunday: Partly sunny, with a high near 41. Calm wind becoming southwest around 6 mph in the afternoon.

    High: 41 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 24. Wind chill values between 15 and 20. West wind 6 to 15 mph becoming northwest after midnight. Winds could gust as high as 25 mph.

    Low: 24 °F

    Partly Cloudy

  • Monday

    Monday: Mostly sunny, with a high near 31. Wind chill values between 10 and 20. North wind 10 to 16 mph, with gusts as high as 29 mph.

    High: 31 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 17. North wind 5 to 9 mph becoming light after midnight.

    Low: 17 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Increasing clouds, with a high near 40.

    High: 40 °F

    Increasing
    Clouds

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 31.

    Low: 31 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: A 40 percent chance of rain. Cloudy, with a high near 47.

    High: 47 °F

    Chance Rain

  • Wednesday Night

    Wednesday Night: A 30 percent chance of rain before 1am. Mostly cloudy, with a low around 35.

    Low: 35 °F

    Chance Rain

Detailed Forecast

Overnight
Partly cloudy, with a low around 30. Northwest wind 3 to 5 mph.
Sunday
Partly sunny, with a high near 41. Calm wind becoming southwest around 6 mph in the afternoon.
Sunday Night
Partly cloudy, with a low around 24. Wind chill values between 15 and 20. West wind 6 to 15 mph becoming northwest after midnight. Winds could gust as high as 25 mph.
Monday
Mostly sunny, with a high near 31. Wind chill values between 10 and 20. North wind 10 to 16 mph, with gusts as high as 29 mph.
Monday Night
Partly cloudy, with a low around 17. North wind 5 to 9 mph becoming light after midnight.
Tuesday
Increasing clouds, with a high near 40.
Tuesday Night
Mostly cloudy, with a low around 31.
Wednesday
A 40 percent chance of rain. Cloudy, with a high near 47.
Wednesday Night
A 30 percent chance of rain before 1am. Mostly cloudy, with a low around 35.
Thursday
Mostly sunny, with a high near 43.
Thursday Night
A chance of rain and snow. Mostly cloudy, with a low around 30. Chance of precipitation is 30%.
Friday
A chance of rain and snow. Mostly cloudy, with a high near 40. Chance of precipitation is 40%.
Friday Night
A chance of rain and snow. Mostly cloudy, with a low around 24. Chance of precipitation is 40%.
Saturday
A 30 percent chance of snow. Partly sunny, with a high near 34.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.92°N 73.12°W (Elev. 112 ft)
Last Update:
12:50 am EST Dec 7, 2025
Forecast Valid:
3am EST Dec 7, 2025-6pm EST Dec 13, 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