Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

Fair

77°F

25°C

Humidity 94%
Wind Speed Calm
Barometer 30.05 in (1017.3 mb)
Dewpoint 75°F (24°C)
Visibility 9.00 mi
Heat Index78°F (26°C)
Last update 16 Jul 2:56 am EDT
Extended Forecast for

Great River NY

Heat Advisory July 16, 11:00am until July 17, 10:00pm
Click here for hazard details and duration
Heat Advisory
  • Overnight

    Overnight: Patchy fog.  Otherwise, partly cloudy, with a low around 73. Calm wind.

    Low: 73 °F

    Patchy Fog

  • Wednesday

    Wednesday: Patchy fog before 8am.  Otherwise, mostly sunny, with a high near 83. Calm wind becoming south 5 to 9 mph in the morning.

    High: 83 °F

    Patchy Fog
    then Mostly
    Sunny

  • Wednesday Night

    Wednesday Night: A 30 percent chance of showers and thunderstorms, mainly between 2am and 5am.  Mostly cloudy, with a low around 74. Southwest wind 6 to 8 mph.

    Low: 74 °F

    Slight Chance
    T-storms then
    Chance
    Showers

  • Thursday

    Thursday: A 40 percent chance of showers and thunderstorms, mainly after 8am.  Partly sunny, with a high near 85. Southwest wind 8 to 13 mph.

    High: 85 °F

    Chance
    T-storms

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 75. Southwest wind around 9 mph.

    Low: 75 °F

    Partly Cloudy

  • Friday

    Friday: Sunny, with a high near 85.

    High: 85 °F

    Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 68.

    Low: 68 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 80.

    High: 80 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: A 30 percent chance of showers after 2am.  Mostly cloudy, with a low around 70.

    Low: 70 °F

    Mostly Cloudy
    then Chance
    Showers

Detailed Forecast

Overnight
Patchy fog. Otherwise, partly cloudy, with a low around 73. Calm wind.
Wednesday
Patchy fog before 8am. Otherwise, mostly sunny, with a high near 83. Calm wind becoming south 5 to 9 mph in the morning.
Wednesday Night
A 30 percent chance of showers and thunderstorms, mainly between 2am and 5am. Mostly cloudy, with a low around 74. Southwest wind 6 to 8 mph.
Thursday
A 40 percent chance of showers and thunderstorms, mainly after 8am. Partly sunny, with a high near 85. Southwest wind 8 to 13 mph.
Thursday Night
Partly cloudy, with a low around 75. Southwest wind around 9 mph.
Friday
Sunny, with a high near 85.
Friday Night
Partly cloudy, with a low around 68.
Saturday
Mostly sunny, with a high near 80.
Saturday Night
A 30 percent chance of showers after 2am. Mostly cloudy, with a low around 70.
Sunday
A chance of showers, with thunderstorms also possible after 2pm. Mostly cloudy, with a high near 81. Chance of precipitation is 50%.
Sunday Night
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 70.
Monday
Mostly sunny, with a high near 81.
Monday Night
Partly cloudy, with a low around 68.
Tuesday
Mostly sunny, with a high near 80.
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ABOUT THIS FORECAST

 
Point Forecast:
Great River NY
 40.72°N 73.16°W (Elev. 13 ft)
2:02 am EDT Jul 16, 2025
3am EDT Jul 16, 2025-6pm EDT Jul 22, 2025
 
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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