National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hazardous Weather Conditions

Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

Fair

72°F

22°C

Humidity 94%
Wind Speed SW 6 mph
Barometer 29.92 in (1013.2 mb)
Dewpoint 70°F (21°C)
Visibility 10.00 mi
Last update 20 Aug 1:56 am EDT
Extended Forecast for

Smithtown NY

  • Overnight

    Overnight: Mostly clear, with a low around 70. Light west wind.

    Low: 70 °F

    Mostly Clear

  • Thursday

    Thursday: A chance of showers, with thunderstorms also possible after 5pm. Increasing clouds, with a high near 82. North wind around 5 mph becoming southwest in the afternoon. Chance of precipitation is 30%.

    High: 82 °F

    Chance
    Showers

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 64. Light northeast wind. Chance of precipitation is 50%.

    Low: 64 °F

    Chance
    Showers

  • Friday

    Friday: A 40 percent chance of showers, mainly after 8am. Mostly cloudy, with a high near 80. East wind around 8 mph.

    High: 80 °F

    Chance
    Showers

  • Friday Night

    Friday Night: A 50 percent chance of showers. Mostly cloudy, with a low around 64. Northeast wind 3 to 6 mph.

    Low: 64 °F

    Chance
    Showers

  • Saturday

    Saturday: Showers likely, with thunderstorms also possible after 2pm. Mostly cloudy, with a high near 79. Chance of precipitation is 60%. New rainfall amounts between a quarter and half of an inch possible.

    High: 79 °F

    Showers
    Likely

  • Saturday Night

    Saturday Night: A chance of showers and thunderstorms, then showers likely after 8pm. Mostly cloudy, with a low around 66. Chance of precipitation is 60%.

    Low: 66 °F

    Chance
    T-storms then
    Showers
    Likely

  • Sunday

    Sunday: Showers likely before 8am, then a chance of showers after 2pm. Partly sunny, with a high near 82. Chance of precipitation is 60%.

    High: 82 °F

    Showers
    Likely then
    Chance
    Showers

  • Sunday Night

    Sunday Night: A 30 percent chance of showers before 8pm. Partly cloudy, with a low around 64.

    Low: 64 °F

    Chance
    Showers then
    Partly Cloudy

Detailed Forecast

Overnight
Mostly clear, with a low around 70. Light west wind.
Thursday
A chance of showers, with thunderstorms also possible after 5pm. Increasing clouds, with a high near 82. North wind around 5 mph becoming southwest in the afternoon. Chance of precipitation is 30%.
Thursday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 64. Light northeast wind. Chance of precipitation is 50%.
Friday
A 40 percent chance of showers, mainly after 8am. Mostly cloudy, with a high near 80. East wind around 8 mph.
Friday Night
A 50 percent chance of showers. Mostly cloudy, with a low around 64. Northeast wind 3 to 6 mph.
Saturday
Showers likely, with thunderstorms also possible after 2pm. Mostly cloudy, with a high near 79. Chance of precipitation is 60%. New rainfall amounts between a quarter and half of an inch possible.
Saturday Night
A chance of showers and thunderstorms, then showers likely after 8pm. Mostly cloudy, with a low around 66. Chance of precipitation is 60%.
Sunday
Showers likely before 8am, then a chance of showers after 2pm. Partly sunny, with a high near 82. Chance of precipitation is 60%.
Sunday Night
A 30 percent chance of showers before 8pm. Partly cloudy, with a low around 64.
Monday
Sunny, with a high near 81.
Monday Night
Mostly clear, with a low around 62.
Tuesday
Sunny, with a high near 80.
Tuesday Night
Partly cloudy, with a low around 64.
Wednesday
Mostly sunny, with a high near 81.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Smithtown NY
 40.86°N 73.19°W (Elev. 98 ft)
Last Update:
2:29 pm EDT Aug 19, 2026
Forecast Valid:
2am EDT Aug 20, 2026-6pm EDT Aug 26, 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