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.

Light Rain Fog/Mist

38°F

3°C

Humidity 89%
Wind Speed Calm
Barometer 30.23 in (1023.7 mb)
Dewpoint 35°F (2°C)
Visibility 4.00 mi
Last update 5 Mar 6:56 am EST
Extended Forecast for

Brentwood NY

  • Today

    Today: Rain. Patchy fog. High near 40. Calm wind becoming northeast 5 to 7 mph in the afternoon. Chance of precipitation is 100%. New precipitation amounts between a quarter and half of an inch possible.

    High: 40 °F

    Rain and
    Patchy Fog

  • Tonight

    Tonight: Rain, mainly before 4am. Patchy fog. Low around 34. East wind 7 to 11 mph, with gusts as high as 23 mph. Chance of precipitation is 100%. New precipitation amounts between a half and three quarters of an inch possible.

    Low: 34 °F

    Rain and
    Patchy Fog

  • Friday

    Friday: A 30 percent chance of rain, mainly before 7am. Patchy fog before 10am. Otherwise, cloudy, with a high near 41. Northeast wind 7 to 10 mph, with gusts as high as 24 mph.

    High: 41 °F

    Chance Rain
    and Patchy
    Fog

  • Friday Night

    Friday Night: A 20 percent chance of rain after 1am. Cloudy, with a low around 34. Northeast wind around 5 mph becoming calm in the evening.

    Low: 34 °F

    Cloudy then
    Slight Chance
    Rain

  • Saturday

    Saturday: Cloudy, with a high near 49. Calm wind becoming south 5 to 7 mph in the afternoon.

    High: 49 °F

    Cloudy

  • Saturday Night

    Saturday Night: Showers likely. Cloudy, with a temperature falling to near 42 by midnight, then rising to around 47 during the remainder of the night. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

    Low: 42 °F⇑

    Showers
    Likely

  • Sunday

    Sunday: Mostly cloudy, with a high near 56.

    High: 56 °F

    Mostly Cloudy

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 39.

    Low: 39 °F

    Partly Cloudy

  • Monday

    Monday: Mostly sunny, with a high near 53.

    High: 53 °F

    Mostly Sunny

Detailed Forecast

Today
Rain. Patchy fog. High near 40. Calm wind becoming northeast 5 to 7 mph in the afternoon. Chance of precipitation is 100%. New precipitation amounts between a quarter and half of an inch possible.
Tonight
Rain, mainly before 4am. Patchy fog. Low around 34. East wind 7 to 11 mph, with gusts as high as 23 mph. Chance of precipitation is 100%. New precipitation amounts between a half and three quarters of an inch possible.
Friday
A 30 percent chance of rain, mainly before 7am. Patchy fog before 10am. Otherwise, cloudy, with a high near 41. Northeast wind 7 to 10 mph, with gusts as high as 24 mph.
Friday Night
A 20 percent chance of rain after 1am. Cloudy, with a low around 34. Northeast wind around 5 mph becoming calm in the evening.
Saturday
Cloudy, with a high near 49. Calm wind becoming south 5 to 7 mph in the afternoon.
Saturday Night
Showers likely. Cloudy, with a temperature falling to near 42 by midnight, then rising to around 47 during the remainder of the night. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.
Sunday
Mostly cloudy, with a high near 56.
Sunday Night
Partly cloudy, with a low around 39.
Monday
Mostly sunny, with a high near 53.
Monday Night
Partly cloudy, with a low around 42.
Tuesday
Partly sunny, with a high near 58.
Tuesday Night
Mostly cloudy, with a low around 42.
Wednesday
Cloudy, with a high near 55.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Brentwood NY
 40.78°N 73.24°W (Elev. 66 ft)
Last Update:
6:25 am EST Mar 5, 2026
Forecast Valid:
7am EST Mar 5, 2026-6pm EDT Mar 11, 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