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

50°F

10°C

Humidity 71%
Wind Speed W 6 mph
Barometer 30.05 in (1017.5 mb)
Dewpoint 41°F (5°C)
Visibility 10.00 mi
Wind Chill48°F (9°C)
Last update 21 Nov 10:56 am EST
Extended Forecast for

Stony Brook NY

  • Today

    Today: A chance of sprinkles before 1pm. Cloudy, with a high near 52. Southwest wind 7 to 9 mph.

    High: 52 °F

    Chance
    Sprinkles

  • Tonight

    Tonight: Rain likely after 1am. Cloudy, with a low around 43. Southwest wind around 6 mph becoming light and variable in the evening. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

    Low: 43 °F

    Cloudy then
    Rain Likely

  • Saturday

    Saturday: A 30 percent chance of rain, mainly before 10am. Cloudy, then gradually becoming mostly sunny, with a high near 50. North wind 6 to 10 mph.

    High: 50 °F

    Chance Rain

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 33. North wind 5 to 8 mph.

    Low: 33 °F

    Partly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 48. West wind 5 to 8 mph.

    High: 48 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 38.

    Low: 38 °F

    Partly Cloudy

  • Monday

    Monday: Sunny, with a high near 52.

    High: 52 °F

    Sunny

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 40.

    Low: 40 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: A 30 percent chance of rain after 1pm. Cloudy, with a high near 56.

    High: 56 °F

    Mostly Cloudy
    then Chance
    Rain

Detailed Forecast

Today
A chance of sprinkles before 1pm. Cloudy, with a high near 52. Southwest wind 7 to 9 mph.
Tonight
Rain likely after 1am. Cloudy, with a low around 43. Southwest wind around 6 mph becoming light and variable in the evening. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Saturday
A 30 percent chance of rain, mainly before 10am. Cloudy, then gradually becoming mostly sunny, with a high near 50. North wind 6 to 10 mph.
Saturday Night
Partly cloudy, with a low around 33. North wind 5 to 8 mph.
Sunday
Mostly sunny, with a high near 48. West wind 5 to 8 mph.
Sunday Night
Partly cloudy, with a low around 38.
Monday
Sunny, with a high near 52.
Monday Night
Mostly cloudy, with a low around 40.
Tuesday
A 30 percent chance of rain after 1pm. Cloudy, with a high near 56.
Tuesday Night
Rain likely. Cloudy, with a low around 48. Chance of precipitation is 70%.
Wednesday
A 50 percent chance of rain. Mostly cloudy, with a high near 59.
Wednesday Night
A 40 percent chance of rain. Mostly cloudy, with a low around 43.
Thanksgiving Day
Partly sunny, with a high near 53.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.92°N 73.12°W (Elev. 112 ft)
Last Update:
10:11 am EST Nov 21, 2025
Forecast Valid:
11am EST Nov 21, 2025-6pm EST Nov 27, 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