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

55°F

13°C

Humidity 74%
Wind Speed NE 15 G 24 mph
Barometer 30.40 in (1029.3 mb)
Dewpoint 47°F (8°C)
Visibility 10.00 mi
Wind Chill51°F (11°C)
Last update 24 Sep 6:56 am EDT
Extended Forecast for

Stony Brook NY

  • Today

    Today: Mostly sunny, with a high near 66. Breezy, with a northeast wind 17 to 21 mph, with gusts as high as 31 mph.

    High: 66 °F

    Mostly Sunny
    and Breezy
    then Mostly
    Sunny

  • Tonight

    Tonight: Mostly cloudy, with a low around 53. Breezy, with a northeast wind 18 to 20 mph, with gusts as high as 30 mph.

    Low: 53 °F

    Mostly Cloudy
    and Breezy

  • Friday

    Friday: A 40 percent chance of showers after 2pm. Mostly cloudy, with a high near 66. Breezy, with a north wind around 22 mph, with gusts as high as 37 mph.

    High: 66 °F

    Breezy.
    Partly Sunny
    then Chance
    Showers

  • Friday Night

    Friday Night: Showers likely, mainly after 2am. Mostly cloudy, with a low around 54. Breezy, with a north wind around 24 mph, with gusts as high as 38 mph. Chance of precipitation is 60%. New precipitation amounts between a quarter and half of an inch possible.

    Low: 54 °F

    Showers
    Likely and
    Breezy

  • Saturday

    Saturday: Showers. High near 64. Breezy, with a north wind around 25 mph, with gusts as high as 39 mph. Chance of precipitation is 80%. New precipitation amounts between a half and three quarters of an inch possible.

    High: 64 °F

    Showers and
    Breezy

  • Saturday Night

    Saturday Night: Showers. Low around 54. Breezy. Chance of precipitation is 80%. New precipitation amounts between three quarters and one inch possible.

    Low: 54 °F

    Showers and
    Breezy

  • Sunday

    Sunday: Showers. High near 65. Breezy. Chance of precipitation is 80%.

    High: 65 °F

    Showers and
    Breezy

  • Sunday Night

    Sunday Night: Showers likely, mainly before 2am. Mostly cloudy, with a low around 55. Chance of precipitation is 60%.

    Low: 55 °F

    Showers
    Likely

  • Monday

    Monday: A 30 percent chance of showers before 8am. Mostly cloudy, with a high near 65.

    High: 65 °F

    Chance
    Showers then
    Partly Sunny

Detailed Forecast

Today
Mostly sunny, with a high near 66. Breezy, with a northeast wind 17 to 21 mph, with gusts as high as 31 mph.
Tonight
Mostly cloudy, with a low around 53. Breezy, with a northeast wind 18 to 20 mph, with gusts as high as 30 mph.
Friday
A 40 percent chance of showers after 2pm. Mostly cloudy, with a high near 66. Breezy, with a north wind around 22 mph, with gusts as high as 37 mph.
Friday Night
Showers likely, mainly after 2am. Mostly cloudy, with a low around 54. Breezy, with a north wind around 24 mph, with gusts as high as 38 mph. Chance of precipitation is 60%. New precipitation amounts between a quarter and half of an inch possible.
Saturday
Showers. High near 64. Breezy, with a north wind around 25 mph, with gusts as high as 39 mph. Chance of precipitation is 80%. New precipitation amounts between a half and three quarters of an inch possible.
Saturday Night
Showers. Low around 54. Breezy. Chance of precipitation is 80%. New precipitation amounts between three quarters and one inch possible.
Sunday
Showers. High near 65. Breezy. Chance of precipitation is 80%.
Sunday Night
Showers likely, mainly before 2am. Mostly cloudy, with a low around 55. Chance of precipitation is 60%.
Monday
A 30 percent chance of showers before 8am. Mostly cloudy, with a high near 65.
Monday Night
Mostly cloudy, with a low around 54.
Tuesday
Mostly sunny, with a high near 68.
Tuesday Night
Partly cloudy, with a low around 56.
Wednesday
Mostly sunny, with a high near 70.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.9°N 73.12°W (Elev. 148 ft)
Last Update:
3:06 am EDT Sep 24, 2026
Forecast Valid:
7am EDT Sep 24, 2026-6pm EDT Sep 30, 2026
 
Forecast Discussion
 
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Additional Resources

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Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation