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.

Partly Cloudy

78°F

26°C

Humidity 85%
Wind Speed S 9 mph
Barometer 30.05 in (1017.3 mb)
Dewpoint 73°F (23°C)
Visibility 10.00 mi
Heat Index80°F (27°C)
Last update 15 Jul 4:56 pm EDT
Extended Forecast for

Stony Brook NY

Heat Advisory July 16, 11:00am until July 17, 10:00pm
Click here for hazard details and duration
Heat Advisory

  • Tonight

    Tonight: Patchy fog before 3am, then patchy fog after 5am. Otherwise, partly cloudy, with a low around 73. South wind around 5 mph becoming calm in the evening.

    Low: 73 °F

    Mostly Clear
    then Patchy
    Fog

  • Wednesday

    Wednesday: Patchy fog before 7am. Otherwise, mostly sunny, with a high near 89. Heat index values as high as 98. Calm wind becoming south 5 to 7 mph in the afternoon.

    High: 89 °F

    Patchy Fog
    then Mostly
    Sunny

  • Wednesday Night

    Wednesday Night: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 75. South wind 6 to 8 mph.

    Low: 75 °F

    Chance
    T-storms

  • Thursday

    Thursday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 2pm. Mostly cloudy, with a high near 89. Heat index values as high as 100. Southwest wind 7 to 11 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 89 °F

    Showers
    Likely

  • Thursday Night

    Thursday Night: Showers likely and possibly a thunderstorm before 8pm. Partly cloudy, with a low around 76. Southwest wind around 8 mph. Chance of precipitation is 60%.

    Low: 76 °F

    Showers
    Likely then
    Partly Cloudy

  • Friday

    Friday: Sunny, with a high near 90.

    High: 90 °F

    Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 69.

    Low: 69 °F

    Partly Cloudy

  • Saturday

    Saturday: Sunny, with a high near 85.

    High: 85 °F

    Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 70.

    Low: 70 °F

    Partly Cloudy

Detailed Forecast

Tonight
Patchy fog before 3am, then patchy fog after 5am. Otherwise, partly cloudy, with a low around 73. South wind around 5 mph becoming calm in the evening.
Wednesday
Patchy fog before 7am. Otherwise, mostly sunny, with a high near 89. Heat index values as high as 98. Calm wind becoming south 5 to 7 mph in the afternoon.
Wednesday Night
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 75. South wind 6 to 8 mph.
Thursday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 2pm. Mostly cloudy, with a high near 89. Heat index values as high as 100. Southwest wind 7 to 11 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Thursday Night
Showers likely and possibly a thunderstorm before 8pm. Partly cloudy, with a low around 76. Southwest wind around 8 mph. Chance of precipitation is 60%.
Friday
Sunny, with a high near 90.
Friday Night
Partly cloudy, with a low around 69.
Saturday
Sunny, with a high near 85.
Saturday Night
Partly cloudy, with a low around 70.
Sunday
A 50 percent chance of showers after 8am. Partly sunny, with a high near 86.
Sunday Night
A 30 percent chance of showers. Mostly cloudy, with a low around 71.
Monday
Mostly sunny, with a high near 86.
Monday Night
Partly cloudy, with a low around 69.
Tuesday
Mostly sunny, with a high near 84.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.92°N 73.12°W (Elev. 112 ft)
Last Update:
3:16 pm EDT Jul 15, 2025
Forecast Valid:
5pm EDT Jul 15, 2025-6pm EDT Jul 22, 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