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

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

Mostly Cloudy

78°F

26°C

Humidity 82%
Wind Speed SW 6 mph
Barometer 29.89 in (1012.1 mb)
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Heat Index80°F (27°C)
Last update 3 Sep 6:56 pm EDT
Extended Forecast for

Brentwood NY

  • Tonight

    Tonight: A 30 percent chance of showers and thunderstorms, mainly before 8pm. Mostly cloudy, with a low around 70. Southwest wind 3 to 5 mph.

    Low: 70 °F

    Chance
    Showers then
    Slight Chance
    T-storms

  • Friday

    Friday: A 20 percent chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 84. Northwest wind 3 to 7 mph.

    High: 84 °F

    Partly Sunny
    then Slight
    Chance
    T-storms

  • Friday Night

    Friday Night: Partly cloudy, with a low around 66. North wind 3 to 6 mph.

    Low: 66 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 79. North wind 7 to 9 mph.

    High: 79 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: A 30 percent chance of showers before 2am. Mostly cloudy, with a low around 62. Northeast wind around 6 mph.

    Low: 62 °F

    Chance
    Showers

  • Sunday

    Sunday: Mostly sunny, with a high near 73.

    High: 73 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 58.

    Low: 58 °F

    Mostly Clear

  • Labor Day

    Labor Day: Sunny, with a high near 76.

    High: 76 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 60.

    Low: 60 °F

    Mostly Clear

Detailed Forecast

Tonight
A 30 percent chance of showers and thunderstorms, mainly before 8pm. Mostly cloudy, with a low around 70. Southwest wind 3 to 5 mph.
Friday
A 20 percent chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 84. Northwest wind 3 to 7 mph.
Friday Night
Partly cloudy, with a low around 66. North wind 3 to 6 mph.
Saturday
Mostly sunny, with a high near 79. North wind 7 to 9 mph.
Saturday Night
A 30 percent chance of showers before 2am. Mostly cloudy, with a low around 62. Northeast wind around 6 mph.
Sunday
Mostly sunny, with a high near 73.
Sunday Night
Mostly clear, with a low around 58.
Labor Day
Sunny, with a high near 76.
Monday Night
Mostly clear, with a low around 60.
Tuesday
Sunny, with a high near 79.
Tuesday Night
Partly cloudy, with a low around 62.
Wednesday
Mostly sunny, with a high near 77.
Wednesday Night
Mostly cloudy, with a low around 67.
Thursday
Partly sunny, with a high near 82.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Brentwood NY
 40.78°N 73.24°W (Elev. 66 ft)
Last Update:
2:25 pm EDT Sep 3, 2026
Forecast Valid:
7pm EDT Sep 3, 2026-6pm EDT Sep 10, 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