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.

Mostly Cloudy

74°F

23°C

Humidity 74%
Wind Speed NW 10 mph
Barometer 30.06 in (1018.0 mb)
Dewpoint 65°F (18°C)
Visibility 10.00 mi
Last update 18 Sep 9:56 am EDT
Extended Forecast for

Brentwood NY

  • Today

    Today: Sunny, with a high near 80. North wind around 9 mph.

    High: 80 °F

    Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 55. Northeast wind 7 to 10 mph.

    Low: 55 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 70. Northeast wind 7 to 10 mph.

    High: 70 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around 57. Southeast wind around 6 mph.

    Low: 57 °F

    Mostly Cloudy

  • Sunday

    Sunday: Showers likely, mainly after 2pm. Mostly cloudy, with a high near 70. Southeast wind 6 to 9 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 70 °F

    Chance
    Showers then
    Showers
    Likely

  • Sunday Night

    Sunday Night: Showers. Low around 60. Chance of precipitation is 90%. New precipitation amounts between 1 and 2 inches possible.

    Low: 60 °F

    Showers

  • Monday

    Monday: Showers likely, mainly before 8am. Mostly cloudy, with a high near 69. Chance of precipitation is 60%.

    High: 69 °F

    Showers
    Likely

  • Monday Night

    Monday Night: A 50 percent chance of showers. Mostly cloudy, with a low around 56.

    Low: 56 °F

    Chance
    Showers

  • Tuesday

    Tuesday: A 40 percent chance of showers. Mostly cloudy, with a high near 65.

    High: 65 °F

    Chance
    Showers

Detailed Forecast

Today
Sunny, with a high near 80. North wind around 9 mph.
Tonight
Partly cloudy, with a low around 55. Northeast wind 7 to 10 mph.
Saturday
Mostly sunny, with a high near 70. Northeast wind 7 to 10 mph.
Saturday Night
Mostly cloudy, with a low around 57. Southeast wind around 6 mph.
Sunday
Showers likely, mainly after 2pm. Mostly cloudy, with a high near 70. Southeast wind 6 to 9 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.
Sunday Night
Showers. Low around 60. Chance of precipitation is 90%. New precipitation amounts between 1 and 2 inches possible.
Monday
Showers likely, mainly before 8am. Mostly cloudy, with a high near 69. Chance of precipitation is 60%.
Monday Night
A 50 percent chance of showers. Mostly cloudy, with a low around 56.
Tuesday
A 40 percent chance of showers. Mostly cloudy, with a high near 65.
Tuesday Night
A 30 percent chance of showers. Mostly cloudy, with a low around 54.
Wednesday
A 30 percent chance of showers. Mostly cloudy, with a high near 65. Breezy.
Wednesday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 54.
Thursday
A 30 percent chance of showers. Partly sunny, with a high near 66.
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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:
5:16 am EDT Sep 18, 2026
Forecast Valid:
10am EDT Sep 18, 2026-6pm EDT Sep 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