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

51°F

11°C

Humidity 43%
Wind Speed NE 10 mph
Barometer 29.93 in (1013.7 mb)
Dewpoint 29°F (-2°C)
Visibility 10.00 mi
Wind Chill47°F (8°C)
Last update 21 Mar 5:56 pm EDT
Extended Forecast for

Brentwood NY

  • Tonight

    Tonight: Mostly cloudy, with a low around 39. North wind 6 to 11 mph becoming light and variable.

    Low: 39 °F

    Mostly Cloudy

  • Sunday

    Sunday: A slight chance of showers before 11am, then a chance of showers after 5pm. Mostly cloudy, with a high near 56. Southwest wind 7 to 11 mph. Chance of precipitation is 30%.

    High: 56 °F

    Chance
    Showers

  • Sunday Night

    Sunday Night: A chance of showers and thunderstorms before 8pm, then showers and possibly a thunderstorm between 8pm and 9pm, then rain after 9pm. Low around 40. West wind around 5 mph becoming north after midnight. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.

    Low: 40 °F

    Showers

  • Monday

    Monday: A 40 percent chance of rain before 2pm. Cloudy, then gradually becoming mostly sunny, with a high near 48. North wind 8 to 10 mph, with gusts as high as 20 mph.

    High: 48 °F

    Chance Rain

  • Monday Night

    Monday Night: Mostly clear, with a low around 30. North wind around 7 mph.

    Low: 30 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 45.

    High: 45 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 34.

    Low: 34 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Partly sunny, with a high near 50.

    High: 50 °F

    Partly Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 35.

    Low: 35 °F

    Mostly Cloudy

Detailed Forecast

Tonight
Mostly cloudy, with a low around 39. North wind 6 to 11 mph becoming light and variable.
Sunday
A slight chance of showers before 11am, then a chance of showers after 5pm. Mostly cloudy, with a high near 56. Southwest wind 7 to 11 mph. Chance of precipitation is 30%.
Sunday Night
A chance of showers and thunderstorms before 8pm, then showers and possibly a thunderstorm between 8pm and 9pm, then rain after 9pm. Low around 40. West wind around 5 mph becoming north after midnight. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.
Monday
A 40 percent chance of rain before 2pm. Cloudy, then gradually becoming mostly sunny, with a high near 48. North wind 8 to 10 mph, with gusts as high as 20 mph.
Monday Night
Mostly clear, with a low around 30. North wind around 7 mph.
Tuesday
Sunny, with a high near 45.
Tuesday Night
Mostly cloudy, with a low around 34.
Wednesday
Partly sunny, with a high near 50.
Wednesday Night
Mostly cloudy, with a low around 35.
Thursday
A chance of rain between 8am and 2pm. Mostly cloudy, with a high near 51. Chance of precipitation is 30%.
Thursday Night
Rain likely. Mostly cloudy, with a low around 40. Chance of precipitation is 60%.
Friday
Mostly sunny, with a high near 50.
Friday Night
Partly cloudy, with a low around 28.
Saturday
Mostly sunny, with a high near 44.
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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:
3:03 pm EDT Mar 21, 2026
Forecast Valid:
6pm EDT Mar 21, 2026-6pm EDT Mar 28, 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