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

43°F

6°C

Humidity 80%
Wind Speed SW 13 mph
Barometer 29.68 in (1005.2 mb)
Dewpoint 37°F (3°C)
Visibility 10.00 mi
Wind Chill36°F (2°C)
Last update 14 Jan 6:56 am EST
Extended Forecast for

Smithtown NY

  • Today

    Today: Mostly cloudy, with a high near 49. Southwest wind 6 to 8 mph.

    High: 49 °F

    Mostly Cloudy

  • Tonight

    Tonight: A 50 percent chance of showers, mainly after 10pm. Cloudy, with a low around 36. Light and variable wind becoming west around 6 mph after midnight.

    Low: 36 °F

    Chance
    Showers

  • Thursday

    Thursday: A slight chance of rain and snow showers before 10am, then a slight chance of snow showers between 10am and 1pm. Partly sunny, with a temperature falling to around 29 by 5pm. Wind chill values between 20 and 30. West wind 7 to 16 mph, with gusts as high as 26 mph. Chance of precipitation is 20%.

    High: 39 °F⇓

    Slight Chance
    Rain/Snow
    then Slight
    Chance Snow
    Showers

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 19. Wind chill values between 5 and 15. West wind around 15 mph, with gusts as high as 30 mph.

    Low: 19 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 35. West wind 11 to 16 mph, with gusts as high as 31 mph.

    High: 35 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Mostly cloudy, with a steady temperature around 31.

    Low: 31 °F

    Mostly Cloudy

  • Saturday

    Saturday: A 30 percent chance of rain after 1pm. Mostly cloudy, with a high near 41.

    High: 41 °F

    Mostly Cloudy
    then Chance
    Rain

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around 26.

    Low: 26 °F

    Mostly Cloudy

  • Sunday

    Sunday: Partly sunny, with a high near 33.

    High: 33 °F

    Partly Sunny

Detailed Forecast

Today
Mostly cloudy, with a high near 49. Southwest wind 6 to 8 mph.
Tonight
A 50 percent chance of showers, mainly after 10pm. Cloudy, with a low around 36. Light and variable wind becoming west around 6 mph after midnight.
Thursday
A slight chance of rain and snow showers before 10am, then a slight chance of snow showers between 10am and 1pm. Partly sunny, with a temperature falling to around 29 by 5pm. Wind chill values between 20 and 30. West wind 7 to 16 mph, with gusts as high as 26 mph. Chance of precipitation is 20%.
Thursday Night
Partly cloudy, with a low around 19. Wind chill values between 5 and 15. West wind around 15 mph, with gusts as high as 30 mph.
Friday
Mostly sunny, with a high near 35. West wind 11 to 16 mph, with gusts as high as 31 mph.
Friday Night
Mostly cloudy, with a steady temperature around 31.
Saturday
A 30 percent chance of rain after 1pm. Mostly cloudy, with a high near 41.
Saturday Night
Mostly cloudy, with a low around 26.
Sunday
Partly sunny, with a high near 33.
Sunday Night
Partly cloudy, with a low around 21.
M.L.King Day
Mostly sunny, with a high near 32.
Monday Night
Mostly cloudy, with a low around 20.
Tuesday
Mostly sunny, with a high near 29.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Smithtown NY
 40.88°N 73.21°W (Elev. 85 ft)
Last Update:
6:04 am EST Jan 14, 2026
Forecast Valid:
7am EST Jan 14, 2026-6pm EST Jan 20, 2026
 
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Additional Resources

Radar & Satellite Image

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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