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

Hazardous Weather Conditions

Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

Light Snow Fog/Mist

32°F

0°C

Humidity 96%
Wind Speed Calm
Barometer 30.08 in (1018.6 mb)
Dewpoint 31°F (-1°C)
Visibility 0.50 mi
Last update 18 Jan 7:56 am EST
Extended Forecast for

Brentwood NY

Winter Weather Advisory until January 19, 04:00am
Click here for hazard details and duration
Winter Weather Advisory
  •  
    Winter Weather Advisory until January 19, 04:00am

    NOW until 4:00am Mon

    Winter Weather Advisory

  • Today

    High: 36 °F

    Rain/Snow

  • Tonight

    Tonight: Snow, mainly before 10pm. Low around 22. Light and variable wind becoming northwest around 6 mph in the evening. Chance of precipitation is 80%. New snow accumulation of 2 to 4 inches possible.

    Low: 22 °F

    Snow then
    Chance Snow

  • M.L.King Day

    M.L.King Day: Mostly sunny, with a high near 32. Wind chill values between 15 and 20. West wind 6 to 15 mph, with gusts as high as 29 mph.

    High: 32 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 15. Wind chill values between 10 and 15. West wind around 11 mph, with gusts as high as 26 mph.

    Low: 15 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Sunny, with a high near 24. West wind 10 to 16 mph, with gusts as high as 29 mph.

    High: 24 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 12.

    Low: 12 °F

    Mostly Clear

  • Wednesday

    Wednesday: Mostly sunny, with a high near 37.

    High: 37 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 28.

    Low: 28 °F

    Mostly Cloudy

Detailed Forecast

Today
Snow, possibly mixed with rain, becoming all snow after 4pm. High near 36. Calm wind becoming northeast around 6 mph in the afternoon. Chance of precipitation is 90%. Total daytime snow accumulation of less than a half inch possible.
Tonight
Snow, mainly before 10pm. Low around 22. Light and variable wind becoming northwest around 6 mph in the evening. Chance of precipitation is 80%. New snow accumulation of 2 to 4 inches possible.
M.L.King Day
Mostly sunny, with a high near 32. Wind chill values between 15 and 20. West wind 6 to 15 mph, with gusts as high as 29 mph.
Monday Night
Partly cloudy, with a low around 15. Wind chill values between 10 and 15. West wind around 11 mph, with gusts as high as 26 mph.
Tuesday
Sunny, with a high near 24. West wind 10 to 16 mph, with gusts as high as 29 mph.
Tuesday Night
Mostly clear, with a low around 12.
Wednesday
Mostly sunny, with a high near 37.
Wednesday Night
Mostly cloudy, with a low around 28.
Thursday
Partly sunny, with a high near 38.
Thursday Night
Partly cloudy, with a low around 20.
Friday
Mostly sunny, with a high near 35.
Friday Night
Mostly cloudy, with a low around 25.
Saturday
A chance of rain and snow. Mostly cloudy, with a high near 37. Chance of precipitation is 30%.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Brentwood NY
 40.75°N 73.24°W (Elev. 49 ft)
Last Update:
4:59 am EST Jan 18, 2026
Forecast Valid:
8am EST Jan 18, 2026-6pm EST Jan 24, 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