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.

Smoke

25°C

77°F

Humidity 74%
Wind Speed S 19 km/h
Barometer 1012.8 mb (29.91 in)
Dewpoint 20°C (68°F)
Visibility 4.02 km
Heat Index26°C (79°F)
Last update 18 Jul 11:56 am EDT
Extended Forecast for

Stony Brook NY

  • This Afternoon

    This Afternoon: Showers and possibly a thunderstorm. Areas of smoke. Steady temperature around 25. South wind around 23 km/h, with gusts as high as 42 km/h. Chance of precipitation is 90%. New rainfall amounts between 1 and 2 cm possible.

    High: 25 °C

    Showers

  • Tonight

    Tonight: Showers and possibly a thunderstorm before 11pm, then a chance of showers and thunderstorms between 11pm and 2am. Low around 22. Southwest wind 18 to 21 km/h, with gusts as high as 42 km/h. Chance of precipitation is 80%. New rainfall amounts between 1 and 2 cm possible.

    Low: 22 °C

    Showers then
    Chance
    T-storms

  • Sunday

    Sunday: Sunny, with a high near 28. Northwest wind 16 to 18 km/h.

    High: 28 °C

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 18. North wind around 11 km/h.

    Low: 18 °C

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 27. North wind 5 to 10 km/h becoming south in the afternoon.

    High: 27 °C

    Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 20.

    Low: 20 °C

    Partly Cloudy

  • Tuesday

    Tuesday: A chance of showers, then showers likely and possibly a thunderstorm after 2pm. Mostly cloudy, with a high near 27. Chance of precipitation is 60%.

    High: 27 °C

    Chance
    Showers then
    Showers
    Likely

  • Tuesday Night

    Tuesday Night: Showers and possibly a thunderstorm. Low around 22. Chance of precipitation is 90%.

    Low: 22 °C

    Showers

  • Wednesday

    Wednesday: Showers likely and possibly a thunderstorm before 2pm, then a chance of showers and thunderstorms after 2pm. Mostly cloudy, with a high near 30. Chance of precipitation is 60%.

    High: 30 °C

    Showers
    Likely

Detailed Forecast

This Afternoon
Showers and possibly a thunderstorm. Areas of smoke. Steady temperature around 25. South wind around 23 km/h, with gusts as high as 42 km/h. Chance of precipitation is 90%. New rainfall amounts between 1 and 2 cm possible.
Tonight
Showers and possibly a thunderstorm before 11pm, then a chance of showers and thunderstorms between 11pm and 2am. Low around 22. Southwest wind 18 to 21 km/h, with gusts as high as 42 km/h. Chance of precipitation is 80%. New rainfall amounts between 1 and 2 cm possible.
Sunday
Sunny, with a high near 28. Northwest wind 16 to 18 km/h.
Sunday Night
Mostly clear, with a low around 18. North wind around 11 km/h.
Monday
Sunny, with a high near 27. North wind 5 to 10 km/h becoming south in the afternoon.
Monday Night
Partly cloudy, with a low around 20.
Tuesday
A chance of showers, then showers likely and possibly a thunderstorm after 2pm. Mostly cloudy, with a high near 27. Chance of precipitation is 60%.
Tuesday Night
Showers and possibly a thunderstorm. Low around 22. Chance of precipitation is 90%.
Wednesday
Showers likely and possibly a thunderstorm before 2pm, then a chance of showers and thunderstorms after 2pm. Mostly cloudy, with a high near 30. Chance of precipitation is 60%.
Wednesday Night
A 30 percent chance of showers before 2am. Mostly cloudy, with a low around 19.
Thursday
Mostly sunny, with a high near 29.
Thursday Night
Partly cloudy, with a low around 19.
Friday
Mostly sunny, with a high near 28.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.92°N 73.12°W (Elev. 112 m)
Last Update:
10:29 am EDT Jul 18, 2026
Forecast Valid:
1pm EDT Jul 18, 2026-6pm EDT Jul 24, 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