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.

A Few Clouds

70°F

21°C

Humidity 41%
Wind Speed S 12 mph
Barometer 30.27 in (1025.0 mb)
Dewpoint 45°F (7°C)
Visibility 10.00 mi
Last update 8 Jun 2:56 pm EDT
Extended Forecast for

Smithtown NY

  • Tonight

    Tonight: Clear, with a low around 56. South wind 5 to 9 mph.

    Low: 56 °F

    Clear

  • Tuesday

    Tuesday: Sunny, with a high near 78. Southwest wind 6 to 13 mph.

    High: 78 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Increasing clouds, with a low around 62. South wind 7 to 10 mph.

    Low: 62 °F

    Increasing
    Clouds

  • Wednesday

    Wednesday: Showers likely, with thunderstorms also possible after 5pm. Mostly cloudy, with a high near 77. South wind 7 to 11 mph. Chance of precipitation is 70%.

    High: 77 °F

    Chance
    Showers then
    Showers
    Likely

  • Wednesday Night

    Wednesday Night: Showers likely and possibly a thunderstorm. Mostly cloudy, with a low around 66. Southwest wind 6 to 9 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 66 °F

    Showers
    Likely

  • Thursday

    Thursday: A 40 percent chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 91.

    High: 91 °F

    Partly Sunny
    then Chance
    T-storms

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 2am. Mostly cloudy, with a low around 66. Chance of precipitation is 40%.

    Low: 66 °F

    Chance
    T-storms then
    Chance
    Showers

  • Friday

    Friday: A 30 percent chance of showers after 2pm. Partly sunny, with a high near 87.

    High: 87 °F

    Partly Sunny
    then Chance
    Showers

  • Friday Night

    Friday Night: A chance of showers before 8pm, then a chance of showers and thunderstorms between 8pm and 2am. Mostly cloudy, with a low around 64. Chance of precipitation is 50%.

    Low: 64 °F

    Chance
    T-storms

Detailed Forecast

Tonight
Clear, with a low around 56. South wind 5 to 9 mph.
Tuesday
Sunny, with a high near 78. Southwest wind 6 to 13 mph.
Tuesday Night
Increasing clouds, with a low around 62. South wind 7 to 10 mph.
Wednesday
Showers likely, with thunderstorms also possible after 5pm. Mostly cloudy, with a high near 77. South wind 7 to 11 mph. Chance of precipitation is 70%.
Wednesday Night
Showers likely and possibly a thunderstorm. Mostly cloudy, with a low around 66. Southwest wind 6 to 9 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Thursday
A 40 percent chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 91.
Thursday Night
A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 2am. Mostly cloudy, with a low around 66. Chance of precipitation is 40%.
Friday
A 30 percent chance of showers after 2pm. Partly sunny, with a high near 87.
Friday Night
A chance of showers before 8pm, then a chance of showers and thunderstorms between 8pm and 2am. Mostly cloudy, with a low around 64. Chance of precipitation is 50%.
Saturday
Mostly sunny, with a high near 86.
Saturday Night
Partly cloudy, with a low around 68.
Sunday
Mostly sunny, with a high near 87.
Sunday Night
A 30 percent chance of showers. Partly cloudy, with a low around 64.
Monday
A 40 percent chance of showers. Partly sunny, with a high near 85.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Smithtown NY
 40.86°N 73.22°W (Elev. 82 ft)
Last Update:
2:07 pm EDT Jun 8, 2026
Forecast Valid:
3pm EDT Jun 8, 2026-6pm EDT Jun 15, 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