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

39°F

4°C

Humidity 60%
Wind Speed SW 16 G 25 mph
Barometer 29.98 in (1015.2 mb)
Dewpoint 26°F (-3°C)
Visibility 10.00 mi
Wind Chill30°F (-1°C)
Last update 9 Dec 8:56 pm EST
Extended Forecast for

Great River NY

  • Tonight

    Tonight: Mostly cloudy, with a steady temperature around 36. Southwest wind around 15 mph, with gusts as high as 26 mph.

    Low: 36 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Rain likely after 1pm. Mostly cloudy, with a high near 49. Breezy, with a southwest wind 16 to 23 mph, with gusts as high as 39 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 49 °F

    Breezy.
    Partly Sunny
    then Rain
    Likely

  • Wednesday Night

    Wednesday Night: A 50 percent chance of rain before 1am. Cloudy, then gradually becoming partly cloudy, with a low around 31. Wind chill values between 25 and 30. Breezy, with a southwest wind 16 to 21 mph, with gusts as high as 33 mph.

    Low: 31 °F

    Chance Rain
    and Breezy

  • Thursday

    Thursday: Mostly sunny, with a high near 37. Wind chill values between 20 and 25. Breezy, with a west wind 18 to 21 mph, with gusts as high as 36 mph.

    High: 37 °F

    Mostly Sunny
    and Breezy

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 25. Breezy, with a west wind 15 to 22 mph, with gusts as high as 37 mph.

    Low: 25 °F

    Partly Cloudy
    and Breezy
    then Partly
    Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 37.

    High: 37 °F

    Mostly Sunny

  • Friday Night

    Friday Night: A 30 percent chance of light snow after 1am. Mostly cloudy, with a low around 27.

    Low: 27 °F

    Mostly Cloudy
    then Chance
    Light Snow

  • Saturday

    Saturday: Mostly cloudy, with a high near 42.

    High: 42 °F

    Mostly Cloudy

  • Saturday Night

    Saturday Night: A 30 percent chance of snow after 1am. Mostly cloudy, with a low around 29.

    Low: 29 °F

    Mostly Cloudy
    then Chance
    Snow

Detailed Forecast

Tonight
Mostly cloudy, with a steady temperature around 36. Southwest wind around 15 mph, with gusts as high as 26 mph.
Wednesday
Rain likely after 1pm. Mostly cloudy, with a high near 49. Breezy, with a southwest wind 16 to 23 mph, with gusts as high as 39 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.
Wednesday Night
A 50 percent chance of rain before 1am. Cloudy, then gradually becoming partly cloudy, with a low around 31. Wind chill values between 25 and 30. Breezy, with a southwest wind 16 to 21 mph, with gusts as high as 33 mph.
Thursday
Mostly sunny, with a high near 37. Wind chill values between 20 and 25. Breezy, with a west wind 18 to 21 mph, with gusts as high as 36 mph.
Thursday Night
Partly cloudy, with a low around 25. Breezy, with a west wind 15 to 22 mph, with gusts as high as 37 mph.
Friday
Mostly sunny, with a high near 37.
Friday Night
A 30 percent chance of light snow after 1am. Mostly cloudy, with a low around 27.
Saturday
Mostly cloudy, with a high near 42.
Saturday Night
A 30 percent chance of snow after 1am. Mostly cloudy, with a low around 29.
Sunday
A chance of snow before 9am, then a chance of rain between 9am and 1pm. Partly sunny, with a high near 39. Chance of precipitation is 40%.
Sunday Night
Partly cloudy, with a low around 20.
Monday
Mostly sunny, with a high near 32.
Monday Night
Mostly cloudy, with a low around 22.
Tuesday
Mostly sunny, with a high near 35.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Great River NY
 40.72°N 73.16°W (Elev. 13 ft)
Last Update:
5:42 pm EST Dec 9, 2025
Forecast Valid:
9pm EST Dec 9, 2025-6pm EST Dec 16, 2025
 
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Additional Resources

Radar & Satellite Image

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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