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

45°F

7°C

Humidity 44%
Wind Speed SW 13 mph
Barometer 29.95 in
Dewpoint 24°F (-4°C)
Visibility 10.00 mi
Wind Chill39°F (4°C)
Last update 13 Jan 1:56 pm EST
Extended Forecast for

Stony Brook NY

  • This Afternoon

    This Afternoon: Mostly sunny, with a high near 44. South wind around 10 mph.

    High: 44 °F

    Mostly Sunny

  • Tonight

    Tonight: A 20 percent chance of rain after 4am. Mostly cloudy, with a low around 39. Southwest wind 10 to 13 mph.

    Low: 39 °F

    Mostly Cloudy
    then Slight
    Chance Rain

  • Wednesday

    Wednesday: A slight chance of rain before 10am, then a slight chance of rain after 4pm. Cloudy, with a high near 47. Southwest wind 6 to 9 mph. Chance of precipitation is 20%.

    High: 47 °F

    Slight Chance
    Rain

  • Wednesday Night

    Wednesday Night: A 50 percent chance of rain, mainly after 1am. Cloudy, with a low around 29. South wind 3 to 7 mph.

    Low: 29 °F

    Slight Chance
    Rain then
    Chance Rain

  • Thursday

    Thursday: A 20 percent chance of snow before 1pm. Cloudy, then gradually becoming mostly sunny, with a temperature rising to near 35 by 10am, then falling to around 28 during the remainder of the day. West wind 10 to 16 mph.

    High: 35 °F⇓

    Slight Chance
    Snow

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 18.

    Low: 18 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 35.

    High: 35 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Mostly cloudy, with a low around 29.

    Low: 29 °F

    Mostly Cloudy

  • Saturday

    Saturday: Partly sunny, with a high near 41.

    High: 41 °F

    Partly Sunny

Detailed Forecast

This Afternoon
Mostly sunny, with a high near 44. South wind around 10 mph.
Tonight
A 20 percent chance of rain after 4am. Mostly cloudy, with a low around 39. Southwest wind 10 to 13 mph.
Wednesday
A slight chance of rain before 10am, then a slight chance of rain after 4pm. Cloudy, with a high near 47. Southwest wind 6 to 9 mph. Chance of precipitation is 20%.
Wednesday Night
A 50 percent chance of rain, mainly after 1am. Cloudy, with a low around 29. South wind 3 to 7 mph.
Thursday
A 20 percent chance of snow before 1pm. Cloudy, then gradually becoming mostly sunny, with a temperature rising to near 35 by 10am, then falling to around 28 during the remainder of the day. West wind 10 to 16 mph.
Thursday Night
Partly cloudy, with a low around 18.
Friday
Mostly sunny, with a high near 35.
Friday Night
Mostly cloudy, with a low around 29.
Saturday
Partly sunny, with a high near 41.
Saturday Night
Mostly cloudy, with a low around 27.
Sunday
Partly sunny, with a high near 33.
Sunday Night
Partly cloudy, with a low around 22.
M.L.King Day
Mostly sunny, with a high near 32.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.92°N 73.15°W (Elev. 36 ft)
Last Update:
12:35 pm EST Jan 13, 2026
Forecast Valid:
2pm EST Jan 13, 2026-6pm EST Jan 19, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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