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.

Overcast

43°F

6°C

Humidity 86%
Wind Speed SW 12 mph
Barometer 29.41 in (995.9 mb)
Dewpoint 39°F (4°C)
Visibility 10.00 mi
Wind Chill37°F (3°C)
Last update 10 Dec 9:56 pm EST
Extended Forecast for

Great River NY

  • Tonight

    Tonight: Cloudy, then gradually becoming partly cloudy, with a low around 29. West wind around 17 mph, with gusts as high as 31 mph.

    Low: 29 °F

    Decreasing
    Clouds

  • Thursday

    Thursday: A 20 percent chance of snow showers after 1pm. Mostly sunny, with a high near 37. Wind chill values between 15 and 25. Breezy, with a west wind 20 to 22 mph, with gusts as high as 43 mph.

    High: 37 °F

    Breezy.
    Mostly Sunny
    then Slight
    Chance Snow
    Showers

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 24. Wind chill values between 10 and 20. Breezy, with a west wind 18 to 23 mph, with gusts as high as 43 mph.

    Low: 24 °F

    Partly Cloudy
    and Breezy

  • Friday

    Friday: Mostly sunny, with a high near 36. Wind chill values between 10 and 20. West wind 13 to 16 mph, with gusts as high as 29 mph.

    High: 36 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 25. West wind 6 to 8 mph.

    Low: 25 °F

    Partly Cloudy

  • Saturday

    Saturday: Partly sunny, with a high near 39.

    High: 39 °F

    Partly Sunny

  • Saturday Night

    Saturday Night: A 40 percent chance of snow after 1am. Mostly cloudy, with a low around 25.

    Low: 25 °F

    Mostly Cloudy
    then Chance
    Snow

  • Sunday

    Sunday: A 40 percent chance of snow before 1pm. Mostly cloudy, with a high near 34.

    High: 34 °F

    Chance Snow

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 19.

    Low: 19 °F

    Partly Cloudy

Detailed Forecast

Tonight
Cloudy, then gradually becoming partly cloudy, with a low around 29. West wind around 17 mph, with gusts as high as 31 mph.
Thursday
A 20 percent chance of snow showers after 1pm. Mostly sunny, with a high near 37. Wind chill values between 15 and 25. Breezy, with a west wind 20 to 22 mph, with gusts as high as 43 mph.
Thursday Night
Partly cloudy, with a low around 24. Wind chill values between 10 and 20. Breezy, with a west wind 18 to 23 mph, with gusts as high as 43 mph.
Friday
Mostly sunny, with a high near 36. Wind chill values between 10 and 20. West wind 13 to 16 mph, with gusts as high as 29 mph.
Friday Night
Partly cloudy, with a low around 25. West wind 6 to 8 mph.
Saturday
Partly sunny, with a high near 39.
Saturday Night
A 40 percent chance of snow after 1am. Mostly cloudy, with a low around 25.
Sunday
A 40 percent chance of snow before 1pm. Mostly cloudy, with a high near 34.
Sunday Night
Partly cloudy, with a low around 19.
Monday
Sunny, with a high near 33.
Monday Night
Mostly cloudy, with a low around 22.
Tuesday
Mostly sunny, with a high near 36.
Tuesday Night
Partly cloudy, with a low around 26.
Wednesday
Partly sunny, with a high near 43.
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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:
5:54 pm EST Dec 10, 2025
Forecast Valid:
10pm EST Dec 10, 2025-6pm EST Dec 17, 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