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.

Overcast

43°F

6°C

Humidity 82%
Wind Speed S 8 mph
Barometer 30.18 in (1022.0 mb)
Dewpoint 38°F (3°C)
Visibility 10.00 mi
Wind Chill38°F (3°C)
Last update 25 Mar 11:56 pm EDT
Extended Forecast for

Stony Brook NY

  • Overnight

    Overnight: A 20 percent chance of rain after 2am. Cloudy, with a steady temperature around 44. South wind around 9 mph.

    Low: 44 °F

    Slight Chance
    Rain

  • Thursday

    Thursday: Cloudy, then gradually becoming mostly sunny, with a high near 59. Southwest wind 10 to 13 mph.

    High: 59 °F

    Decreasing
    Clouds

  • Thursday Night

    Thursday Night: Showers, mainly after 2am. Low around 46. Southwest wind 8 to 11 mph. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.

    Low: 46 °F

    Chance
    Showers then
    Showers

  • Friday

    Friday: Showers, mainly before 2pm. High near 53. North wind 8 to 10 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 53 °F

    Showers

  • Friday Night

    Friday Night: A slight chance of rain showers, mixing with snow after 11pm, then gradually ending. Mostly cloudy, with a low around 30. North wind 6 to 8 mph. Chance of precipitation is 20%.

    Low: 30 °F

    Slight Chance
    Rain/Snow

  • Saturday

    Saturday: Mostly sunny, with a high near 42.

    High: 42 °F

    Mostly Sunny

  • Saturday Night

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

    Low: 29 °F

    Partly Cloudy

  • Sunday

    Sunday: Sunny, with a high near 46.

    High: 46 °F

    Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 36.

    Low: 36 °F

    Partly Cloudy

Detailed Forecast

Overnight
A 20 percent chance of rain after 2am. Cloudy, with a steady temperature around 44. South wind around 9 mph.
Thursday
Cloudy, then gradually becoming mostly sunny, with a high near 59. Southwest wind 10 to 13 mph.
Thursday Night
Showers, mainly after 2am. Low around 46. Southwest wind 8 to 11 mph. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.
Friday
Showers, mainly before 2pm. High near 53. North wind 8 to 10 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.
Friday Night
A slight chance of rain showers, mixing with snow after 11pm, then gradually ending. Mostly cloudy, with a low around 30. North wind 6 to 8 mph. Chance of precipitation is 20%.
Saturday
Mostly sunny, with a high near 42.
Saturday Night
Partly cloudy, with a low around 29.
Sunday
Sunny, with a high near 46.
Sunday Night
Partly cloudy, with a low around 36.
Monday
Mostly cloudy, with a high near 52.
Monday Night
Mostly cloudy, with a low around 42.
Tuesday
Mostly cloudy, with a high near 52.
Tuesday Night
A 40 percent chance of rain. Mostly cloudy, with a low around 39.
Wednesday
A 30 percent chance of rain. Mostly cloudy, with a high near 52.
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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:
11:15 pm EDT Mar 25, 2026
Forecast Valid:
12am EDT Mar 26, 2026-6pm EDT Apr 1, 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