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

81°F

27°C

Humidity 69%
Wind Speed Calm
Barometer 30.01 in (1016.1 mb)
Dewpoint 70°F (21°C)
Visibility 10.00 mi
Heat Index84°F (29°C)
Last update 25 Jun 12:56 am EDT
Extended Forecast for

Stony Brook NY

Heat Advisory June 25, 01:26am until June 25, 07:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory June 25, 01:26am until June 25, 07:00pm

    NOW until 7:00pm Wed

    Heat Advisory

  • Overnight

    Low: 75 °F

    Mostly Clear

  • Wednesday

    Wednesday: A 20 percent chance of showers and thunderstorms after 2pm. Sunny, with a high near 93. Heat index values as high as 99. Northwest wind 3 to 7 mph.

    High: 93 °F

    Sunny then
    Slight Chance
    T-storms

  • Wednesday Night

    Wednesday Night: A 40 percent chance of showers and thunderstorms, mainly after 8pm. Partly cloudy, with a low around 68. Light and variable wind becoming northeast around 6 mph after midnight.

    Low: 68 °F

    Chance
    T-storms then
    Chance
    Showers

  • Thursday

    Thursday: A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a steady temperature around 70. East wind 9 to 13 mph.

    High: 70 °F

    Chance
    Showers

  • Thursday Night

    Thursday Night: A 40 percent chance of showers and thunderstorms. Cloudy, with a low around 62. East wind 7 to 11 mph.

    Low: 62 °F

    Chance
    Showers

  • Friday

    Friday: A 30 percent chance of showers before 2pm. Mostly cloudy, with a high near 71.

    High: 71 °F

    Chance
    Showers

  • Friday Night

    Friday Night: A chance of thunderstorms before 8pm, then a chance of showers and thunderstorms after 8pm. Mostly cloudy, with a low around 64. Chance of precipitation is 30%.

    Low: 64 °F

    Chance
    T-storms

  • Saturday

    Saturday: A 40 percent chance of showers and thunderstorms after 2pm. Mostly cloudy, with a high near 77.

    High: 77 °F

    Mostly Cloudy
    then Chance
    T-storms

Detailed Forecast

Overnight
Mostly clear, with a low around 75. Light northwest wind.
Wednesday
A 20 percent chance of showers and thunderstorms after 2pm. Sunny, with a high near 93. Heat index values as high as 99. Northwest wind 3 to 7 mph.
Wednesday Night
A 40 percent chance of showers and thunderstorms, mainly after 8pm. Partly cloudy, with a low around 68. Light and variable wind becoming northeast around 6 mph after midnight.
Thursday
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a steady temperature around 70. East wind 9 to 13 mph.
Thursday Night
A 40 percent chance of showers and thunderstorms. Cloudy, with a low around 62. East wind 7 to 11 mph.
Friday
A 30 percent chance of showers before 2pm. Mostly cloudy, with a high near 71.
Friday Night
A chance of thunderstorms before 8pm, then a chance of showers and thunderstorms after 8pm. Mostly cloudy, with a low around 64. Chance of precipitation is 30%.
Saturday
A 40 percent chance of showers and thunderstorms after 2pm. Mostly cloudy, with a high near 77.
Saturday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 66. Chance of precipitation is 40%.
Sunday
A 30 percent chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 78.
Sunday Night
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 67.
Monday
A 30 percent chance of showers. Partly sunny, with a high near 83.
Monday Night
A 30 percent chance of showers. Mostly cloudy, with a low around 70.
Tuesday
A 40 percent chance of showers and thunderstorms. Partly sunny, with a high near 86.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.9°N 73.12°W (Elev. 148 ft)
Last Update:
6:59 pm EDT Jun 24, 2025
Forecast Valid:
1am EDT Jun 25, 2025-6pm EDT Jul 1, 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