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

30°F

-1°C

Humidity 49%
Wind Speed S 8 mph
Barometer 30.11 in (1019.9 mb)
Dewpoint 13°F (-11°C)
Visibility 10.00 mi
Wind Chill22°F (-6°C)
Last update 9 Dec 2:56 pm EST
Extended Forecast for

Great River NY

  • Tonight

    Tonight: Mostly cloudy, with a temperature rising to around 37 by 10pm. Wind chill values between 25 and 30. Southwest wind 11 to 15 mph, with gusts as high as 26 mph.

    Low: 32 °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 38. Wind chill values between 20 and 25. Breezy, with a west wind 18 to 21 mph, with gusts as high as 36 mph.

    High: 38 °F

    Mostly Sunny
    and Breezy

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 26. Breezy, with a west wind 15 to 22 mph, with gusts as high as 37 mph.

    Low: 26 °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 temperature rising to around 37 by 10pm. Wind chill values between 25 and 30. Southwest wind 11 to 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 38. 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 26. 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:
1:17 pm EST Dec 9, 2025
Forecast Valid:
3pm EST Dec 9, 2025-6pm EST Dec 16, 2025
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation