National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hazardous Weather Conditions

Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

Fair

65°F

18°C

Humidity 81%
Wind Speed SW 9 mph
Barometer 30.11 in (1019.4 mb)
Dewpoint 59°F (15°C)
Visibility 10.00 mi
Last update 19 May 3:56 am EDT
Extended Forecast for

Stony Brook NY

  • Today

    Today: Sunny, with a high near 89. South wind 8 to 14 mph.

    High: 89 °F

    Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 70. Southwest wind around 11 mph.

    Low: 70 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Showers and possibly a thunderstorm after 2pm. High near 87. Southwest wind 9 to 14 mph. Chance of precipitation is 90%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 87 °F

    Sunny then
    Showers

  • Wednesday Night

    Wednesday Night: Showers and possibly a thunderstorm before 8pm, then a chance of showers. Low around 59. North wind 6 to 10 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 59 °F

    Showers then
    Chance
    Showers

  • Thursday

    Thursday: Partly sunny, with a high near 74. North wind 5 to 9 mph becoming light and variable in the afternoon.

    High: 74 °F

    Partly Sunny

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 55.

    Low: 55 °F

    Mostly Cloudy

  • Friday

    Friday: Partly sunny, with a high near 69.

    High: 69 °F

    Partly Sunny

  • Friday Night

    Friday Night: Showers likely, mainly after 2am. Cloudy, with a low around 52. Chance of precipitation is 70%.

    Low: 52 °F

    Chance
    Showers then
    Showers
    Likely

  • Saturday

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

    High: 65 °F

    Showers

Detailed Forecast

Today
Sunny, with a high near 89. South wind 8 to 14 mph.
Tonight
Partly cloudy, with a low around 70. Southwest wind around 11 mph.
Wednesday
Showers and possibly a thunderstorm after 2pm. High near 87. Southwest wind 9 to 14 mph. Chance of precipitation is 90%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Wednesday Night
Showers and possibly a thunderstorm before 8pm, then a chance of showers. Low around 59. North wind 6 to 10 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Thursday
Partly sunny, with a high near 74. North wind 5 to 9 mph becoming light and variable in the afternoon.
Thursday Night
Mostly cloudy, with a low around 55.
Friday
Partly sunny, with a high near 69.
Friday Night
Showers likely, mainly after 2am. Cloudy, with a low around 52. Chance of precipitation is 70%.
Saturday
Showers. High near 65. Chance of precipitation is 80%.
Saturday Night
Showers. Low around 54. Chance of precipitation is 80%.
Sunday
Showers likely. Mostly cloudy, with a high near 70. Chance of precipitation is 60%.
Sunday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 56.
Memorial Day
Mostly cloudy, with a high near 74.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.92°N 73.15°W (Elev. 36 ft)
Last Update:
2:21 am EDT May 19, 2026
Forecast Valid:
4am EDT May 19, 2026-6pm EDT May 25, 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