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.

Overcast

71°F

22°C

Humidity 84%
Wind Speed N 9 mph
Barometer 30.05 in (1017.6 mb)
Dewpoint 66°F (19°C)
Visibility 10.00 mi
Last update 21 Aug 2:56 pm EDT
Extended Forecast for

Nissequogue NY

  • This Afternoon

    This Afternoon: A 30 percent chance of showers. Partly sunny, with a high near 76. Northeast wind around 10 mph.

    High: 76 °F

    Chance
    Showers

  • Tonight

    Tonight: Mostly cloudy, with a low around 63. Northeast wind 5 to 7 mph.

    Low: 63 °F

    Mostly Cloudy

  • Saturday

    Saturday: A 20 percent chance of showers after 2pm. Mostly cloudy, with a high near 75. Northeast wind around 6 mph.

    High: 75 °F

    Mostly Cloudy
    then Slight
    Chance
    Showers

  • Saturday Night

    Saturday Night: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 65. East wind 3 to 5 mph.

    Low: 65 °F

    Chance
    Showers

  • Sunday

    Sunday: A 50 percent chance of showers and thunderstorms. Partly sunny, with a high near 80. East wind 5 to 7 mph becoming south in the afternoon.

    High: 80 °F

    Chance
    Showers

  • Sunday Night

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

    Low: 65 °F

    Partly Cloudy

  • Monday

    Monday: Sunny, with a high near 80.

    High: 80 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 62.

    Low: 62 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 78.

    High: 78 °F

    Sunny

Detailed Forecast

This Afternoon
A 30 percent chance of showers. Partly sunny, with a high near 76. Northeast wind around 10 mph.
Tonight
Mostly cloudy, with a low around 63. Northeast wind 5 to 7 mph.
Saturday
A 20 percent chance of showers after 2pm. Mostly cloudy, with a high near 75. Northeast wind around 6 mph.
Saturday Night
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 65. East wind 3 to 5 mph.
Sunday
A 50 percent chance of showers and thunderstorms. Partly sunny, with a high near 80. East wind 5 to 7 mph becoming south in the afternoon.
Sunday Night
Partly cloudy, with a low around 65.
Monday
Sunny, with a high near 80.
Monday Night
Mostly clear, with a low around 62.
Tuesday
Sunny, with a high near 78.
Tuesday Night
Mostly clear, with a low around 63.
Wednesday
Sunny, with a high near 81.
Wednesday Night
A 30 percent chance of showers. Partly cloudy, with a low around 66.
Thursday
A 40 percent chance of showers. Partly sunny, with a high near 80.
Thursday Night
A 50 percent chance of showers. Mostly cloudy, with a low around 67.
Friday
Partly sunny, with a high near 82.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Nissequogue NY
 40.9°N 73.18°W (Elev. 7 ft)
Last Update:
2:49 pm EDT Aug 21, 2026
Forecast Valid:
3pm EDT Aug 21, 2026-6pm EDT Aug 28, 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