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

47°F

8°C

Humidity 97%
Wind Speed NE 8 mph
Barometer 29.70 in (1005.8 mb)
Dewpoint 46°F (8°C)
Visibility 7.00 mi
Wind Chill43°F (6°C)
Last update 23 Mar 4:56 am EDT
Extended Forecast for

Brentwood NY

  • Overnight

    Overnight: Rain. Steady temperature around 45. Northeast wind around 6 mph. Chance of precipitation is 90%. New precipitation amounts of less than a tenth of an inch possible.

    Low: 45 °F

    Rain

  • Monday

    Monday: Rain, mainly before 11am, then a slight chance of showers after 2pm. Temperature falling to around 40 by 1pm. North wind around 10 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 45 °F⇓

    Rain then
    Chance Rain

  • Monday Night

    Monday Night: Mostly cloudy, then gradually becoming mostly clear, with a low around 31. Wind chill values between 25 and 30. Northwest wind 6 to 9 mph, with gusts as high as 20 mph.

    Low: 31 °F

    Decreasing
    Clouds

  • Tuesday

    Tuesday: Sunny, with a high near 46. Wind chill values between 25 and 35 early. North wind 6 to 8 mph.

    High: 46 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Increasing clouds, with a low around 34. Southwest wind around 6 mph.

    Low: 34 °F

    Increasing
    Clouds

  • Wednesday

    Wednesday: Partly sunny, with a high near 51.

    High: 51 °F

    Partly Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 40.

    Low: 40 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly cloudy, with a high near 55.

    High: 55 °F

    Mostly Cloudy

  • Thursday Night

    Thursday Night: Rain likely after 2am. Mostly cloudy, with a low around 44. Chance of precipitation is 60%.

    Low: 44 °F

    Mostly Cloudy
    then Rain
    Likely

Detailed Forecast

Overnight
Rain. Steady temperature around 45. Northeast wind around 6 mph. Chance of precipitation is 90%. New precipitation amounts of less than a tenth of an inch possible.
Monday
Rain, mainly before 11am, then a slight chance of showers after 2pm. Temperature falling to around 40 by 1pm. North wind around 10 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.
Monday Night
Mostly cloudy, then gradually becoming mostly clear, with a low around 31. Wind chill values between 25 and 30. Northwest wind 6 to 9 mph, with gusts as high as 20 mph.
Tuesday
Sunny, with a high near 46. Wind chill values between 25 and 35 early. North wind 6 to 8 mph.
Tuesday Night
Increasing clouds, with a low around 34. Southwest wind around 6 mph.
Wednesday
Partly sunny, with a high near 51.
Wednesday Night
Mostly cloudy, with a low around 40.
Thursday
Mostly cloudy, with a high near 55.
Thursday Night
Rain likely after 2am. Mostly cloudy, with a low around 44. Chance of precipitation is 60%.
Friday
Rain likely, mainly before 8am. Partly sunny, with a high near 54. Chance of precipitation is 60%.
Friday Night
Partly cloudy, with a low around 28.
Saturday
Mostly sunny, with a high near 42.
Saturday Night
Mostly clear, with a low around 30.
Sunday
Sunny, with a high near 47.
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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:
2:12 am EDT Mar 23, 2026
Forecast Valid:
5am EDT Mar 23, 2026-6pm EDT Mar 29, 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