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

76°F

24°C

Humidity 67%
Wind Speed Calm
Barometer 29.92 in (1013.0 mb)
Dewpoint 64°F (18°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 13 Aug 9:56 pm EDT
Extended Forecast for

Islandia NY

  • Tonight

    Tonight: Partly cloudy, with a low around 68. Light northwest wind.

    Low: 68 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 85. North wind 3 to 6 mph.

    High: 85 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 65. Calm wind becoming northeast around 5 mph after midnight.

    Low: 65 °F

    Partly Cloudy

  • Saturday

    Saturday: Sunny, with a high near 83. Northeast wind around 7 mph.

    High: 83 °F

    Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 65. South wind around 5 mph becoming calm in the evening.

    Low: 65 °F

    Partly Cloudy

  • Sunday

    Sunday: Showers likely after 2pm. Partly sunny, with a high near 81. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 81 °F

    Mostly Sunny
    then Showers
    Likely

  • Sunday Night

    Sunday Night: Showers likely before 8pm, then showers and possibly a thunderstorm between 8pm and 2am, then a chance of showers after 2am. Low around 68. Chance of precipitation is 80%.

    Low: 68 °F

    Showers

  • Monday

    Monday: A 30 percent chance of showers before 8am. Partly sunny, with a high near 84.

    High: 84 °F

    Chance
    Showers then
    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 65.

    Low: 65 °F

    Partly Cloudy

Detailed Forecast

Tonight
Partly cloudy, with a low around 68. Light northwest wind.
Friday
Mostly sunny, with a high near 85. North wind 3 to 6 mph.
Friday Night
Partly cloudy, with a low around 65. Calm wind becoming northeast around 5 mph after midnight.
Saturday
Sunny, with a high near 83. Northeast wind around 7 mph.
Saturday Night
Partly cloudy, with a low around 65. South wind around 5 mph becoming calm in the evening.
Sunday
Showers likely after 2pm. Partly sunny, with a high near 81. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.
Sunday Night
Showers likely before 8pm, then showers and possibly a thunderstorm between 8pm and 2am, then a chance of showers after 2am. Low around 68. Chance of precipitation is 80%.
Monday
A 30 percent chance of showers before 8am. Partly sunny, with a high near 84.
Monday Night
Partly cloudy, with a low around 65.
Tuesday
Sunny, with a high near 83.
Tuesday Night
Mostly clear, with a low around 67.
Wednesday
Sunny, with a high near 83.
Wednesday Night
Partly cloudy, with a low around 69.
Thursday
A 30 percent chance of showers. Mostly sunny, with a high near 85.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Islandia NY
 40.81°N 73.17°W (Elev. 161 ft)
Last Update:
8:32 pm EDT Aug 13, 2026
Forecast Valid:
10pm EDT Aug 13, 2026-6pm EDT Aug 20, 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