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

61°F

16°C

Humidity 84%
Wind Speed Calm
Barometer 30.00 in (1016.0 mb)
Dewpoint 56°F (13°C)
Visibility 10.00 mi
Last update 14 Apr 7:56 am EDT
Extended Forecast for

Stony Brook NY

  • Today

    Today: Mostly sunny, with a high near 79. Light southwest wind becoming south 5 to 10 mph in the afternoon.

    High: 79 °F

    Mostly Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 56. Southwest wind 6 to 9 mph.

    Low: 56 °F

    Partly Cloudy

  • Wednesday

    Wednesday: A 20 percent chance of showers after 2pm. Mostly sunny, with a high near 80. South wind 5 to 10 mph.

    High: 80 °F

    Mostly Sunny
    then Slight
    Chance
    Showers

  • Wednesday Night

    Wednesday Night: A chance of showers and thunderstorms before 11pm, then a chance of showers between 11pm and 2am. Mostly cloudy, with a low around 55. Southwest wind around 6 mph. Chance of precipitation is 40%.

    Low: 55 °F

    Chance
    Showers

  • Thursday

    Thursday: Partly sunny, with a high near 76. Light southwest wind becoming south 5 to 9 mph in the morning.

    High: 76 °F

    Partly Sunny

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 55.

    Low: 55 °F

    Mostly Cloudy

  • Friday

    Friday: A 40 percent chance of showers after 8am. Partly sunny, with a high near 71.

    High: 71 °F

    Chance
    Showers

  • Friday Night

    Friday Night: Mostly cloudy, with a low around 50.

    Low: 50 °F

    Mostly Cloudy

  • Saturday

    Saturday: Partly sunny, with a high near 62.

    High: 62 °F

    Partly Sunny

Detailed Forecast

Today
Mostly sunny, with a high near 79. Light southwest wind becoming south 5 to 10 mph in the afternoon.
Tonight
Partly cloudy, with a low around 56. Southwest wind 6 to 9 mph.
Wednesday
A 20 percent chance of showers after 2pm. Mostly sunny, with a high near 80. South wind 5 to 10 mph.
Wednesday Night
A chance of showers and thunderstorms before 11pm, then a chance of showers between 11pm and 2am. Mostly cloudy, with a low around 55. Southwest wind around 6 mph. Chance of precipitation is 40%.
Thursday
Partly sunny, with a high near 76. Light southwest wind becoming south 5 to 9 mph in the morning.
Thursday Night
Mostly cloudy, with a low around 55.
Friday
A 40 percent chance of showers after 8am. Partly sunny, with a high near 71.
Friday Night
Mostly cloudy, with a low around 50.
Saturday
Partly sunny, with a high near 62.
Saturday Night
Mostly cloudy, with a low around 49.
Sunday
A 40 percent chance of showers. Mostly cloudy, with a high near 63.
Sunday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 43.
Monday
Mostly sunny, with a high near 55.
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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:
7:51 am EDT Apr 14, 2026
Forecast Valid:
8am EDT Apr 14, 2026-6pm EDT Apr 20, 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