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

44°F

7°C

Humidity 49%
Wind Speed S 17 G 22 mph
Barometer 29.93 in
Dewpoint 26°F (-3°C)
Visibility 10.00 mi
Wind Chill36°F (2°C)
Last update 13 Jan 2:56 pm EST
Extended Forecast for

Smithtown NY

  • Tonight

    Tonight: A 20 percent chance of rain after 4am. Mostly cloudy, with a low around 38. Southwest wind 8 to 10 mph, with gusts as high as 20 mph.

    Low: 38 °F

    Mostly Cloudy
    then Slight
    Chance Rain

  • Wednesday

    Wednesday: A slight chance of rain before 10am, then a slight chance of rain after 4pm. Mostly cloudy, with a high near 47. South wind 6 to 8 mph. Chance of precipitation is 20%.

    High: 47 °F

    Slight Chance
    Rain

  • Wednesday Night

    Wednesday Night: A 50 percent chance of rain, mainly after 1am. Cloudy, with a low around 29. Calm wind becoming southwest around 6 mph after midnight.

    Low: 29 °F

    Slight Chance
    Rain then
    Chance Rain

  • Thursday

    Thursday: A 20 percent chance of snow before 1pm. Mostly sunny, with a temperature rising to near 35 by 10am, then falling to around 28 during the remainder of the day. Wind chill values between 15 and 25. West wind 9 to 14 mph, with gusts as high as 24 mph.

    High: 35 °F⇓

    Slight Chance
    Snow

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 17. West wind 10 to 13 mph.

    Low: 17 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 35.

    High: 35 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Mostly cloudy, with a low around 27.

    Low: 27 °F

    Mostly Cloudy

  • Saturday

    Saturday: Partly sunny, with a high near 41.

    High: 41 °F

    Partly Sunny

  • Saturday Night

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

    Low: 26 °F

    Mostly Cloudy

Detailed Forecast

Tonight
A 20 percent chance of rain after 4am. Mostly cloudy, with a low around 38. Southwest wind 8 to 10 mph, with gusts as high as 20 mph.
Wednesday
A slight chance of rain before 10am, then a slight chance of rain after 4pm. Mostly cloudy, with a high near 47. South wind 6 to 8 mph. Chance of precipitation is 20%.
Wednesday Night
A 50 percent chance of rain, mainly after 1am. Cloudy, with a low around 29. Calm wind becoming southwest around 6 mph after midnight.
Thursday
A 20 percent chance of snow before 1pm. Mostly sunny, with a temperature rising to near 35 by 10am, then falling to around 28 during the remainder of the day. Wind chill values between 15 and 25. West wind 9 to 14 mph, with gusts as high as 24 mph.
Thursday Night
Partly cloudy, with a low around 17. West wind 10 to 13 mph.
Friday
Mostly sunny, with a high near 35.
Friday Night
Mostly cloudy, with a low around 27.
Saturday
Partly sunny, 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 31.
Monday Night
Partly cloudy, with a low around 18.
Tuesday
Mostly sunny, with a high near 27.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Smithtown NY
 40.88°N 73.21°W (Elev. 85 ft)
Last Update:
12:35 pm EST Jan 13, 2026
Forecast Valid:
3pm EST Jan 13, 2026-6pm EST Jan 20, 2026
 
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Additional Resources

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Hourly Weather Forecast

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation