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

38°F

3°C

Humidity 55%
Wind Speed Calm
Barometer 30.04 in (1017.2 mb)
Dewpoint 23°F (-5°C)
Visibility 10.00 mi
Last update 3 Dec 4:56 pm EST
Extended Forecast for

Stony Brook NY

  • Tonight

    Tonight: Mostly clear, with a low around 30. Wind chill values between 20 and 25. West wind 3 to 8 mph.

    Low: 30 °F

    Mostly Clear

  • Thursday

    Thursday: Increasing clouds, with a high near 40. Wind chill values between 25 and 30. West wind 9 to 16 mph, with gusts as high as 31 mph.

    High: 40 °F

    Increasing
    Clouds

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 17. Wind chill values between 10 and 15. Northwest wind 12 to 17 mph decreasing to 6 to 11 mph after midnight. Winds could gust as high as 32 mph.

    Low: 17 °F

    Mostly Clear

  • Friday

    Friday: A 20 percent chance of light snow after 1pm. Increasing clouds, with a high near 33. Wind chill values between 10 and 20. Light and variable wind becoming southeast around 6 mph in the morning.

    High: 33 °F

    Mostly Sunny
    then Slight
    Chance Light
    Snow

  • Friday Night

    Friday Night: A 30 percent chance of light snow. Cloudy, with a low around 27. South wind around 5 mph becoming light and variable in the evening.

    Low: 27 °F

    Chance Light
    Snow

  • Saturday

    Saturday: A 30 percent chance of rain before 1pm. Partly sunny, with a high near 39.

    High: 39 °F

    Chance Rain

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 29.

    Low: 29 °F

    Partly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 42.

    High: 42 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Mostly cloudy, with a low around 23.

    Low: 23 °F

    Mostly Cloudy

Detailed Forecast

Tonight
Mostly clear, with a low around 30. Wind chill values between 20 and 25. West wind 3 to 8 mph.
Thursday
Increasing clouds, with a high near 40. Wind chill values between 25 and 30. West wind 9 to 16 mph, with gusts as high as 31 mph.
Thursday Night
Mostly clear, with a low around 17. Wind chill values between 10 and 15. Northwest wind 12 to 17 mph decreasing to 6 to 11 mph after midnight. Winds could gust as high as 32 mph.
Friday
A 20 percent chance of light snow after 1pm. Increasing clouds, with a high near 33. Wind chill values between 10 and 20. Light and variable wind becoming southeast around 6 mph in the morning.
Friday Night
A 30 percent chance of light snow. Cloudy, with a low around 27. South wind around 5 mph becoming light and variable in the evening.
Saturday
A 30 percent chance of rain before 1pm. Partly sunny, with a high near 39.
Saturday Night
Partly cloudy, with a low around 29.
Sunday
Mostly sunny, with a high near 42.
Sunday Night
Mostly cloudy, with a low around 23.
Monday
Mostly sunny, with a high near 31.
Monday Night
Partly cloudy, with a low around 18.
Tuesday
Mostly sunny, with a high near 37.
Tuesday Night
A 30 percent chance of snow. Mostly cloudy, with a low around 28.
Wednesday
A chance of rain and snow. Mostly cloudy, with a high near 44. Chance of precipitation is 30%.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.92°N 73.12°W (Elev. 112 ft)
Last Update:
4:09 pm EST Dec 3, 2025
Forecast Valid:
5pm EST Dec 3, 2025-6pm EST Dec 10, 2025
 
Forecast Discussion
 
Get as KML Get as XML

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