Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

A Few Clouds

77°F

25°C

Humidity 94%
Wind Speed SW 5 mph
Barometer 30.05 in (1017.6 mb)
Dewpoint 75°F (24°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 15 Jul 11:56 pm 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: Mostly sunny, with a high near 83. Calm wind becoming south 5 to 9 mph in the morning.

    High: 83 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: A 50 percent chance of showers and thunderstorms.  Mostly cloudy, with a low around 74. Southwest wind around 8 mph.

    Low: 74 °F

    Chance
    T-storms

  • Thursday

    Thursday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 2pm.  Partly sunny, with a high near 84. Southwest wind 8 to 13 mph.  Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 84 °F

    Showers
    Likely

  • Thursday Night

    Thursday Night: Showers likely and possibly a thunderstorm before 8pm.  Partly cloudy, with a low around 76. Southwest wind 7 to 9 mph.  Chance of precipitation is 60%.

    Low: 76 °F

    Showers
    Likely then
    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 86.

    High: 86 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 69.

    Low: 69 °F

    Partly Cloudy

  • Saturday

    Saturday: Sunny, with a high near 81.

    High: 81 °F

    Sunny

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around 70.

    Low: 70 °F

    Mostly Cloudy

Detailed Forecast

Overnight
Patchy fog. Otherwise, partly cloudy, with a low around 73. Calm wind.
Wednesday
Mostly sunny, with a high near 83. Calm wind becoming south 5 to 9 mph in the morning.
Wednesday Night
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 74. Southwest wind around 8 mph.
Thursday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 2pm. Partly sunny, with a high near 84. Southwest wind 8 to 13 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Thursday Night
Showers likely and possibly a thunderstorm before 8pm. Partly cloudy, with a low around 76. Southwest wind 7 to 9 mph. Chance of precipitation is 60%.
Friday
Mostly sunny, with a high near 86.
Friday Night
Partly cloudy, with a low around 69.
Saturday
Sunny, with a high near 81.
Saturday Night
Mostly cloudy, with a low around 70.
Sunday
A 40 percent chance of showers after 8am. Partly sunny, with a high near 81.
Sunday Night
A 30 percent chance of showers. Mostly cloudy, with a low around 70.
Monday
Mostly sunny, with a high near 83.
Monday Night
Partly cloudy, with a low around 69.
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)
3:16 pm EDT Jul 15, 2025
12am EDT Jul 16, 2025-6pm EDT Jul 22, 2025
 
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Additional Resources

Radar & Satellite Image

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Hourly Weather Forecast

National Digital Forecast Database