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.

Overcast

77°F

25°C

Humidity 88%
Wind Speed S 9 mph
Barometer 30.13 in (1020.3 mb)
Dewpoint 73°F (23°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 5 Aug 5:56 pm EDT
Extended Forecast for

Stony Brook NY

Heat Advisory August 6, 11:00am until August 7, 08:00pm
Click here for hazard details and duration
Heat Advisory

  • Tonight

    Tonight: A slight chance of showers before 2am, then a slight chance of showers after 5am. Mostly cloudy, with a low around 74. South wind around 6 mph. Chance of precipitation is 20%.

    Low: 74 °F

    Slight Chance
    Showers

  • Thursday

    Thursday: Mostly sunny, with a high near 88. Heat index values as high as 99. Southwest wind 6 to 10 mph.

    High: 88 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 75. Southwest wind 5 to 8 mph.

    Low: 75 °F

    Partly Cloudy

  • Friday

    Friday: A 40 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 88. Heat index values as high as 98. Southwest wind 5 to 8 mph.

    High: 88 °F

    Mostly Sunny
    then Chance
    T-storms

  • Friday Night

    Friday Night: A 40 percent chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 74. Southwest wind 5 to 7 mph.

    Low: 74 °F

    Chance
    T-storms then
    Chance
    Showers

  • Saturday

    Saturday: Mostly sunny, with a high near 88.

    High: 88 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: A 30 percent chance of showers before 2am. Partly cloudy, with a low around 72.

    Low: 72 °F

    Chance
    Showers

  • Sunday

    Sunday: Sunny, with a high near 88.

    High: 88 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 71.

    Low: 71 °F

    Mostly Clear

Detailed Forecast

Tonight
A slight chance of showers before 2am, then a slight chance of showers after 5am. Mostly cloudy, with a low around 74. South wind around 6 mph. Chance of precipitation is 20%.
Thursday
Mostly sunny, with a high near 88. Heat index values as high as 99. Southwest wind 6 to 10 mph.
Thursday Night
Partly cloudy, with a low around 75. Southwest wind 5 to 8 mph.
Friday
A 40 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 88. Heat index values as high as 98. Southwest wind 5 to 8 mph.
Friday Night
A 40 percent chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 74. Southwest wind 5 to 7 mph.
Saturday
Mostly sunny, with a high near 88.
Saturday Night
A 30 percent chance of showers before 2am. Partly cloudy, with a low around 72.
Sunday
Sunny, with a high near 88.
Sunday Night
Mostly clear, with a low around 71.
Monday
Sunny, with a high near 88.
Monday Night
Partly cloudy, with a low around 72.
Tuesday
A 40 percent chance of showers. Mostly sunny, with a high near 88.
Tuesday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 70.
Wednesday
Mostly sunny, with a high near 84.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.9°N 73.12°W (Elev. 148 ft)
Last Update:
2:06 pm EDT Aug 5, 2026
Forecast Valid:
6pm EDT Aug 5, 2026-6pm EDT Aug 12, 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