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

45°F

7°C

Humidity 58%
Wind Speed SW 7 mph
Barometer 29.85 in (1010.9 mb)
Dewpoint 31°F (-1°C)
Visibility 10.00 mi
Wind Chill41°F (5°C)
Last update 6 Dec 2:56 pm EST
Extended Forecast for

Smithtown NY

  • Tonight

    Tonight: Mostly clear, with a low around 28. West wind around 6 mph becoming calm after midnight.

    Low: 28 °F

    Mostly Clear

  • Sunday

    Sunday: Partly sunny, with a high near 41. Calm wind becoming south around 6 mph in the afternoon.

    High: 41 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 23. Light west wind becoming northwest 5 to 9 mph in the evening.

    Low: 23 °F

    Partly Cloudy

  • Monday

    Monday: Mostly sunny, with a high near 31. Wind chill values between 15 and 20. North wind 10 to 14 mph, with gusts as high as 24 mph.

    High: 31 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 16. North wind 5 to 8 mph becoming calm after midnight.

    Low: 16 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Increasing clouds, with a high near 39.

    High: 39 °F

    Increasing
    Clouds

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 30.

    Low: 30 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: A 40 percent chance of rain after 1pm. Mostly cloudy, with a high near 47.

    High: 47 °F

    Mostly Cloudy
    then Chance
    Rain

  • Wednesday Night

    Wednesday Night: A 40 percent chance of rain. Mostly cloudy, with a low around 33.

    Low: 33 °F

    Chance Rain

Detailed Forecast

Tonight
Mostly clear, with a low around 28. West wind around 6 mph becoming calm after midnight.
Sunday
Partly sunny, with a high near 41. Calm wind becoming south around 6 mph in the afternoon.
Sunday Night
Partly cloudy, with a low around 23. Light west wind becoming northwest 5 to 9 mph in the evening.
Monday
Mostly sunny, with a high near 31. Wind chill values between 15 and 20. North wind 10 to 14 mph, with gusts as high as 24 mph.
Monday Night
Partly cloudy, with a low around 16. North wind 5 to 8 mph becoming calm after midnight.
Tuesday
Increasing clouds, with a high near 39.
Tuesday Night
Mostly cloudy, with a low around 30.
Wednesday
A 40 percent chance of rain after 1pm. Mostly cloudy, with a high near 47.
Wednesday Night
A 40 percent chance of rain. Mostly cloudy, with a low around 33.
Thursday
A 30 percent chance of rain before 1pm. Partly sunny, with a high near 44.
Thursday Night
A 40 percent chance of rain. Mostly cloudy, with a low around 29.
Friday
A 30 percent chance of rain. Partly sunny, with a high near 41.
Friday Night
A 30 percent chance of snow. Partly cloudy, with a low around 23.
Saturday
Mostly sunny, with a high near 34.
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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:
12:55 pm EST Dec 6, 2025
Forecast Valid:
3pm EST Dec 6, 2025-6pm EST Dec 13, 2025
 
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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