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 and Breezy

50°F

10°C

Humidity 29%
Wind Speed NW 22 G 33 mph
Barometer 29.95 in (1014.3 mb)
Dewpoint 19°F (-7°C)
Visibility 10.00 mi
Wind Chill43°F (6°C)
Last update 14 Mar 1:56 pm EDT
Extended Forecast for

Stony Brook NY

  • This Afternoon

    This Afternoon: Sunny, with a high near 50. Breezy, with a west wind around 21 mph, with gusts as high as 38 mph.

    High: 50 °F

    Sunny and
    Breezy

  • Tonight

    Tonight: Increasing clouds, with a low around 33. Northwest wind 5 to 15 mph.

    Low: 33 °F

    Increasing
    Clouds

  • Sunday

    Sunday: Partly sunny, with a high near 49. Northeast wind 6 to 11 mph becoming southeast in the afternoon.

    High: 49 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Showers after 2am. Temperature falling to near 41 by 9pm, then rising to around 49 during the remainder of the night. Southeast wind 9 to 15 mph. Chance of precipitation is 90%. New precipitation amounts between a quarter and half of an inch possible.

    Low: 41 °F⇑

    Mostly Cloudy
    then Showers

  • Monday

    Monday: Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. High near 59. Breezy, with a south wind 20 to 24 mph, with gusts as high as 40 mph. Chance of precipitation is 100%. New rainfall amounts between a half and three quarters of an inch possible.

    High: 59 °F

    Heavy Rain
    and Breezy

  • Monday Night

    Monday Night: Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. Low around 34. Windy. Chance of precipitation is 100%. New precipitation amounts between a half and three quarters of an inch possible.

    Low: 34 °F

    Heavy Rain
    and Windy

  • Tuesday

    Tuesday: A 30 percent chance of showers before 8am. Mostly sunny, with a high near 42. Breezy.

    High: 42 °F

    Breezy.
    Chance
    Showers then
    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 25.

    Low: 25 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 38.

    High: 38 °F

    Mostly Sunny

Detailed Forecast

This Afternoon
Sunny, with a high near 50. Breezy, with a west wind around 21 mph, with gusts as high as 38 mph.
Tonight
Increasing clouds, with a low around 33. Northwest wind 5 to 15 mph.
Sunday
Partly sunny, with a high near 49. Northeast wind 6 to 11 mph becoming southeast in the afternoon.
Sunday Night
Showers after 2am. Temperature falling to near 41 by 9pm, then rising to around 49 during the remainder of the night. Southeast wind 9 to 15 mph. Chance of precipitation is 90%. New precipitation amounts between a quarter and half of an inch possible.
Monday
Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. High near 59. Breezy, with a south wind 20 to 24 mph, with gusts as high as 40 mph. Chance of precipitation is 100%. New rainfall amounts between a half and three quarters of an inch possible.
Monday Night
Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. Low around 34. Windy. Chance of precipitation is 100%. New precipitation amounts between a half and three quarters of an inch possible.
Tuesday
A 30 percent chance of showers before 8am. Mostly sunny, with a high near 42. Breezy.
Tuesday Night
Partly cloudy, with a low around 25.
Wednesday
Mostly sunny, with a high near 38.
Wednesday Night
Mostly cloudy, with a low around 30.
Thursday
Mostly sunny, with a high near 45.
Thursday Night
Mostly cloudy, with a low around 34.
Friday
Mostly sunny, with a high near 49.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.92°N 73.15°W (Elev. 36 ft)
Last Update:
2:22 pm EDT Mar 14, 2026
Forecast Valid:
2pm EDT Mar 14, 2026-6pm EDT Mar 20, 2026
 
Forecast Discussion
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation