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.

Mostly Cloudy

75°F

24°C

Humidity 84%
Wind Speed SW 7 mph
Barometer 29.86 in (1010.8 mb)
Dewpoint 70°F (21°C)
Visibility 10.00 mi
Last update 10 Sep 8:56 pm EDT
Extended Forecast for

Islip, Long Island Mac Arthur Airport NY

  • Tonight

    Tonight: Mostly cloudy, with a low around 66. Light north wind.

    Low: 66 °F

    Mostly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 79. North wind 3 to 7 mph.

    High: 79 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 59. Calm wind.

    Low: 59 °F

    Mostly Clear

  • Saturday

    Saturday: Mostly sunny, with a high near 77. Light and variable wind becoming south 5 to 9 mph in the morning.

    High: 77 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Showers likely and possibly a thunderstorm after 2am. Mostly cloudy, with a low around 67. South wind around 7 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.

    Low: 67 °F

    Mostly Cloudy
    then Showers
    Likely

  • Sunday

    Sunday: Showers likely before 2pm. Mostly cloudy, with a high near 79. Chance of precipitation is 70%. New precipitation amounts between a half and three quarters of an inch possible.

    High: 79 °F

    Showers
    Likely

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 64.

    Low: 64 °F

    Partly Cloudy

  • Monday

    Monday: Mostly sunny, with a high near 76.

    High: 76 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 59.

    Low: 59 °F

    Partly Cloudy

Detailed Forecast

Tonight
Mostly cloudy, with a low around 66. Light north wind.
Friday
Mostly sunny, with a high near 79. North wind 3 to 7 mph.
Friday Night
Mostly clear, with a low around 59. Calm wind.
Saturday
Mostly sunny, with a high near 77. Light and variable wind becoming south 5 to 9 mph in the morning.
Saturday Night
Showers likely and possibly a thunderstorm after 2am. Mostly cloudy, with a low around 67. South wind around 7 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.
Sunday
Showers likely before 2pm. Mostly cloudy, with a high near 79. Chance of precipitation is 70%. New precipitation amounts between a half and three quarters of an inch possible.
Sunday Night
Partly cloudy, with a low around 64.
Monday
Mostly sunny, with a high near 76.
Monday Night
Partly cloudy, with a low around 59.
Tuesday
Sunny, with a high near 72.
Tuesday Night
Mostly clear, with a low around 62.
Wednesday
Sunny, with a high near 77.
Wednesday Night
Partly cloudy, with a low around 64.
Thursday
A 30 percent chance of showers. Mostly sunny, with a high near 77.
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ABOUT THIS FORECAST

 
Point Forecast:
Islip, Long Island Mac Arthur Airport NY
 40.78°N 73.09°W (Elev. 49 ft)
Last Update:
9:48 pm EDT Sep 10, 2026
Forecast Valid:
10pm EDT Sep 10, 2026-6pm EDT Sep 17, 2026
 
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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