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.

Overcast

41°F

5°C

Humidity 89%
Wind Speed Calm
Barometer 30.08 in (1018.5 mb)
Dewpoint 38°F (3°C)
Visibility 10.00 mi
Last update 7 Apr 4:56 am EDT
Extended Forecast for

Brentwood NY

  • Overnight

    Overnight: A 20 percent chance of showers. Mostly cloudy, with a low around 40. Southeast wind around 6 mph.

    Low: 40 °F

    Slight Chance
    Showers

  • Tuesday

    Tuesday: Mostly sunny, with a high near 53. Breezy, with a southwest wind 8 to 13 mph becoming northwest 15 to 20 mph in the afternoon. Winds could gust as high as 31 mph.

    High: 53 °F

    Partly Sunny
    then Mostly
    Sunny and
    Breezy

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 29. Wind chill values between 20 and 25. North wind 9 to 16 mph.

    Low: 29 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 46. Wind chill values between 20 and 30 early. North wind 8 to 10 mph becoming southeast in the afternoon.

    High: 46 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 30. South wind 3 to 7 mph.

    Low: 30 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny, with a high near 50.

    High: 50 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 38.

    Low: 38 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 57.

    High: 57 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 45.

    Low: 45 °F

    Partly Cloudy

Detailed Forecast

Overnight
A 20 percent chance of showers. Mostly cloudy, with a low around 40. Southeast wind around 6 mph.
Tuesday
Mostly sunny, with a high near 53. Breezy, with a southwest wind 8 to 13 mph becoming northwest 15 to 20 mph in the afternoon. Winds could gust as high as 31 mph.
Tuesday Night
Mostly clear, with a low around 29. Wind chill values between 20 and 25. North wind 9 to 16 mph.
Wednesday
Sunny, with a high near 46. Wind chill values between 20 and 30 early. North wind 8 to 10 mph becoming southeast in the afternoon.
Wednesday Night
Mostly clear, with a low around 30. South wind 3 to 7 mph.
Thursday
Mostly sunny, with a high near 50.
Thursday Night
Partly cloudy, with a low around 38.
Friday
Mostly sunny, with a high near 57.
Friday Night
Partly cloudy, with a low around 45.
Saturday
Mostly sunny, with a high near 64.
Saturday Night
Mostly clear, with a low around 43.
Sunday
Sunny, with a high near 57.
Sunday Night
Mostly cloudy, with a low around 45.
Monday
Partly sunny, with a high near 65.
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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:
4:36 am EDT Apr 7, 2026
Forecast Valid:
5am EDT Apr 7, 2026-6pm EDT Apr 13, 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