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 94%
Wind Speed SW 5 mph
Barometer 29.97 in (1014.8 mb)
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Last update 27 Aug 7:56 pm EDT
Extended Forecast for

Great River NY

  • Tonight

    Tonight: A 20 percent chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 71. South wind 7 to 10 mph.

    Low: 71 °F

    Slight Chance
    T-storms

  • Friday

    Friday: A 30 percent chance of showers and thunderstorms, mainly after 2pm. Partly sunny, with a high near 81. Southwest wind 3 to 8 mph.

    High: 81 °F

    Slight Chance
    T-storms then
    Chance
    Showers

  • Friday Night

    Friday Night: A 30 percent chance of showers and thunderstorms, mainly before 8pm. Mostly cloudy, with a low around 66. Light and variable wind becoming north 5 to 8 mph after midnight.

    Low: 66 °F

    Chance
    Showers then
    Mostly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 80. North wind 5 to 7 mph becoming east in the afternoon.

    High: 80 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 65. Light south wind.

    Low: 65 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 81.

    High: 81 °F

    Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 70.

    Low: 70 °F

    Partly Cloudy

  • Monday

    Monday: A 30 percent chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 82.

    High: 82 °F

    Partly Sunny
    then Chance
    T-storms

  • Monday Night

    Monday Night: A 30 percent chance of showers and thunderstorms before 8pm. Mostly cloudy, with a low around 71.

    Low: 71 °F

    Chance
    T-storms then
    Mostly Cloudy

Detailed Forecast

Tonight
A 20 percent chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 71. South wind 7 to 10 mph.
Friday
A 30 percent chance of showers and thunderstorms, mainly after 2pm. Partly sunny, with a high near 81. Southwest wind 3 to 8 mph.
Friday Night
A 30 percent chance of showers and thunderstorms, mainly before 8pm. Mostly cloudy, with a low around 66. Light and variable wind becoming north 5 to 8 mph after midnight.
Saturday
Mostly sunny, with a high near 80. North wind 5 to 7 mph becoming east in the afternoon.
Saturday Night
Mostly clear, with a low around 65. Light south wind.
Sunday
Sunny, with a high near 81.
Sunday Night
Partly cloudy, with a low around 70.
Monday
A 30 percent chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 82.
Monday Night
A 30 percent chance of showers and thunderstorms before 8pm. Mostly cloudy, with a low around 71.
Tuesday
A 30 percent chance of showers after 2pm. Partly sunny, with a high near 81.
Tuesday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 70.
Wednesday
A 40 percent chance of showers. Partly sunny, with a high near 80.
Wednesday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 69.
Thursday
Partly sunny, with a high near 80.
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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:
8:06 pm EDT Aug 27, 2026
Forecast Valid:
8pm EDT Aug 27, 2026-6pm EDT Sep 3, 2026
 
Forecast Discussion
 
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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