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.

A Few Clouds and Breezy

34°F

1°C

Humidity 54%
Wind Speed NW 21 G 36 mph
Barometer 29.92 in (1013.3 mb)
Dewpoint 19°F (-7°C)
Visibility 10.00 mi
Wind Chill22°F (-6°C)
Last update 11 Jan 11:56 pm EST
Extended Forecast for

Great River NY

  • Overnight

    Overnight: Mostly clear, with a low around 29. Wind chill values between 20 and 25. West wind around 16 mph, with gusts as high as 36 mph.

    Low: 29 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 41. Wind chill values between 20 and 30. West wind 11 to 14 mph, with gusts as high as 28 mph.

    High: 41 °F

    Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 32. West wind 7 to 10 mph, with gusts as high as 22 mph.

    Low: 32 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Sunny, with a high near 45. Southwest wind 6 to 10 mph.

    High: 45 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a steady temperature around 40. Southwest wind around 10 mph, with gusts as high as 23 mph.

    Low: 40 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Mostly cloudy, with a high near 47.

    High: 47 °F

    Mostly Cloudy

  • Wednesday Night

    Wednesday Night: A 40 percent chance of rain after 1am. Cloudy, with a low around 34.

    Low: 34 °F

    Cloudy then
    Chance Rain

  • Thursday

    Thursday: A 40 percent chance of rain. Mostly cloudy, with a high near 43.

    High: 43 °F

    Chance Rain

  • Thursday Night

    Thursday Night: A chance of rain and snow before 1am, then a chance of snow. Mostly cloudy, with a low around 23. Chance of precipitation is 40%.

    Low: 23 °F

    Chance
    Rain/Snow

Detailed Forecast

Overnight
Mostly clear, with a low around 29. Wind chill values between 20 and 25. West wind around 16 mph, with gusts as high as 36 mph.
Monday
Sunny, with a high near 41. Wind chill values between 20 and 30. West wind 11 to 14 mph, with gusts as high as 28 mph.
Monday Night
Partly cloudy, with a low around 32. West wind 7 to 10 mph, with gusts as high as 22 mph.
Tuesday
Sunny, with a high near 45. Southwest wind 6 to 10 mph.
Tuesday Night
Mostly cloudy, with a steady temperature around 40. Southwest wind around 10 mph, with gusts as high as 23 mph.
Wednesday
Mostly cloudy, with a high near 47.
Wednesday Night
A 40 percent chance of rain after 1am. Cloudy, with a low around 34.
Thursday
A 40 percent chance of rain. Mostly cloudy, with a high near 43.
Thursday Night
A chance of rain and snow before 1am, then a chance of snow. Mostly cloudy, with a low around 23. Chance of precipitation is 40%.
Friday
Mostly sunny, with a high near 35.
Friday Night
Partly cloudy, with a low around 26.
Saturday
Mostly sunny, with a high near 39.
Saturday Night
Mostly cloudy, with a low around 27.
Sunday
A 40 percent chance of rain. Partly sunny, with a high near 37.
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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:
1:42 pm EST Jan 11, 2026
Forecast Valid:
1am EST Jan 12, 2026-6pm EST Jan 18, 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