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.

Fair

41°F

5°C

Humidity 76%
Wind Speed Calm
Barometer 30.17 in (1021.6 mb)
Dewpoint 34°F (1°C)
Visibility 10.00 mi
Last update 2 Nov 1:56 am EST
Extended Forecast for

Stony Brook NY

  • Overnight

    Overnight: Partly cloudy, with a low around 41. Northwest wind around 6 mph.

    Low: 41 °F

    Partly Cloudy

  • Sunday

    Sunday: Sunny, with a high near 57. Northwest wind around 6 mph becoming southwest in the afternoon.

    High: 57 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 46. Light southwest wind.

    Low: 46 °F

    Mostly Clear

  • Monday

    Monday: A 40 percent chance of rain after 1pm. Partly sunny, with a high near 61. Light south wind increasing to 8 to 13 mph in the morning.

    High: 61 °F

    Partly Sunny
    then Chance
    Rain

  • Monday Night

    Monday Night: A 20 percent chance of rain before 1am. Mostly cloudy, then gradually becoming clear, with a low around 46. Southwest wind 10 to 13 mph becoming northwest after midnight. Winds could gust as high as 24 mph.

    Low: 46 °F

    Slight Chance
    Rain

  • Tuesday

    Tuesday: Sunny, with a high near 59.

    High: 59 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 45.

    Low: 45 °F

    Mostly Clear

  • Wednesday

    Wednesday: Partly sunny, with a high near 61.

    High: 61 °F

    Partly Sunny

  • Wednesday Night

    Wednesday Night: A 40 percent chance of rain. Mostly cloudy, with a low around 44.

    Low: 44 °F

    Chance Rain

Detailed Forecast

Overnight
Partly cloudy, with a low around 41. Northwest wind around 6 mph.
Sunday
Sunny, with a high near 57. Northwest wind around 6 mph becoming southwest in the afternoon.
Sunday Night
Mostly clear, with a low around 46. Light southwest wind.
Monday
A 40 percent chance of rain after 1pm. Partly sunny, with a high near 61. Light south wind increasing to 8 to 13 mph in the morning.
Monday Night
A 20 percent chance of rain before 1am. Mostly cloudy, then gradually becoming clear, with a low around 46. Southwest wind 10 to 13 mph becoming northwest after midnight. Winds could gust as high as 24 mph.
Tuesday
Sunny, with a high near 59.
Tuesday Night
Mostly clear, with a low around 45.
Wednesday
Partly sunny, with a high near 61.
Wednesday Night
A 40 percent chance of rain. Mostly cloudy, with a low around 44.
Thursday
Mostly sunny, with a high near 56.
Thursday Night
Mostly clear, with a low around 40.
Friday
Partly sunny, with a high near 60.
Friday Night
A 50 percent chance of rain. Mostly cloudy, with a low around 49.
Saturday
A 40 percent chance of rain. Mostly sunny, with a high near 61.
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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:
1:04 am EST Nov 2, 2025
Forecast Valid:
2am EST Nov 2, 2025-6pm EST Nov 8, 2025
 
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