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

79°F

26°C

Humidity 79%
Wind Speed SW 8 mph
Barometer 29.86 in (1011.0 mb)
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Heat Index82°F (28°C)
Last update 18 Aug 3:56 pm EDT
Extended Forecast for

Islip NYSimilar City Names

  • This Afternoon

    This Afternoon: A 20 percent chance of showers before 5pm. Partly sunny, with a steady temperature around 81. South wind around 7 mph.

    High: 81 °F

    Slight Chance
    Showers

  • Tonight

    Tonight: Increasing clouds, with a low around 69. Southwest wind around 5 mph becoming calm in the evening.

    Low: 69 °F

    Increasing
    Clouds

  • Wednesday

    Wednesday: Mostly cloudy through mid morning, then gradual clearing, with a high near 85. Calm wind becoming southwest 5 to 8 mph in the afternoon.

    High: 85 °F

    Becoming
    Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 71. Southwest wind 3 to 7 mph.

    Low: 71 °F

    Partly Cloudy

  • Thursday

    Thursday: A 40 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 84. Light and variable wind becoming west around 6 mph in the afternoon.

    High: 84 °F

    Mostly Sunny
    then Chance
    Showers

  • Thursday Night

    Thursday Night: A 30 percent chance of showers before 2am. Mostly cloudy, with a low around 65.

    Low: 65 °F

    Chance
    Showers

  • Friday

    Friday: Mostly sunny, with a high near 81.

    High: 81 °F

    Mostly Sunny

  • Friday Night

    Friday Night: A 40 percent chance of showers after 2am. Mostly cloudy, with a low around 65.

    Low: 65 °F

    Mostly Cloudy
    then Chance
    Showers

  • Saturday

    Saturday: A 50 percent chance of showers. Partly sunny, with a high near 79.

    High: 79 °F

    Chance
    Showers

Detailed Forecast

This Afternoon
A 20 percent chance of showers before 5pm. Partly sunny, with a steady temperature around 81. South wind around 7 mph.
Tonight
Increasing clouds, with a low around 69. Southwest wind around 5 mph becoming calm in the evening.
Wednesday
Mostly cloudy through mid morning, then gradual clearing, with a high near 85. Calm wind becoming southwest 5 to 8 mph in the afternoon.
Wednesday Night
Partly cloudy, with a low around 71. Southwest wind 3 to 7 mph.
Thursday
A 40 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 84. Light and variable wind becoming west around 6 mph in the afternoon.
Thursday Night
A 30 percent chance of showers before 2am. Mostly cloudy, with a low around 65.
Friday
Mostly sunny, with a high near 81.
Friday Night
A 40 percent chance of showers after 2am. Mostly cloudy, with a low around 65.
Saturday
A 50 percent chance of showers. Partly sunny, with a high near 79.
Saturday Night
A 50 percent chance of showers. Mostly cloudy, with a low around 66.
Sunday
A 40 percent chance of showers. Partly sunny, with a high near 81.
Sunday Night
A 30 percent chance of showers. Partly cloudy, with a low around 65.
Monday
Sunny, with a high near 82.
Monday Night
Mostly clear, with a low around 64.
Tuesday
Sunny, with a high near 81.
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ABOUT THIS FORECAST

 
Point Forecast:
Islip NYSimilar City Names
 40.73°N 73.22°W (Elev. 7 ft)
Last Update:
2:34 pm EDT Aug 18, 2026
Forecast Valid:
4pm EDT Aug 18, 2026-6pm EDT Aug 25, 2026
 
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Additional Resources

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Chance of Precipitation