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

39°F

4°C

Humidity 43%
Wind Speed N 5 mph
Barometer 30.29 in (1025.8 mb)
Dewpoint 18°F (-8°C)
Visibility 10.00 mi
Wind Chill35°F (2°C)
Last update 1 Dec 4:56 pm EST
Extended Forecast for

Smithtown NY

  • Tonight

    Tonight: Increasing clouds, with a low around 29. Calm wind becoming southeast around 6 mph after midnight.

    Low: 29 °F

    Increasing
    Clouds

  • Tuesday

    Tuesday: Rain. High near 46. Southeast wind 5 to 15 mph becoming north in the afternoon. Winds could gust as high as 26 mph. Chance of precipitation is 100%. New precipitation amounts between three quarters and one inch possible.

    High: 46 °F

    Rain

  • Tuesday Night

    Tuesday Night: Rain, mainly before 10pm. Low around 29. Wind chill values between 20 and 25. Northwest wind 13 to 17 mph, with gusts as high as 30 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

    Low: 29 °F

    Rain then
    Slight Chance
    Rain

  • Wednesday

    Wednesday: Sunny, with a high near 40. Wind chill values between 20 and 30. Northwest wind 5 to 10 mph, with gusts as high as 22 mph.

    High: 40 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 29. Calm wind becoming west around 6 mph after midnight.

    Low: 29 °F

    Partly Cloudy

  • Thursday

    Thursday: Partly sunny, with a high near 41.

    High: 41 °F

    Partly Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 19.

    Low: 19 °F

    Mostly Clear

  • Friday

    Friday: Mostly sunny, with a high near 37.

    High: 37 °F

    Mostly Sunny

  • Friday Night

    Friday Night: A 30 percent chance of snow after 1am. Mostly cloudy, with a low around 25.

    Low: 25 °F

    Mostly Cloudy
    then Chance
    Snow

Detailed Forecast

Tonight
Increasing clouds, with a low around 29. Calm wind becoming southeast around 6 mph after midnight.
Tuesday
Rain. High near 46. Southeast wind 5 to 15 mph becoming north in the afternoon. Winds could gust as high as 26 mph. Chance of precipitation is 100%. New precipitation amounts between three quarters and one inch possible.
Tuesday Night
Rain, mainly before 10pm. Low around 29. Wind chill values between 20 and 25. Northwest wind 13 to 17 mph, with gusts as high as 30 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.
Wednesday
Sunny, with a high near 40. Wind chill values between 20 and 30. Northwest wind 5 to 10 mph, with gusts as high as 22 mph.
Wednesday Night
Partly cloudy, with a low around 29. Calm wind becoming west around 6 mph after midnight.
Thursday
Partly sunny, with a high near 41.
Thursday Night
Mostly clear, with a low around 19.
Friday
Mostly sunny, with a high near 37.
Friday Night
A 30 percent chance of snow after 1am. Mostly cloudy, with a low around 25.
Saturday
A 30 percent chance of rain before 1pm. Partly sunny, with a high near 42.
Saturday Night
Mostly cloudy, with a low around 30.
Sunday
Partly sunny, with a high near 42.
Sunday Night
Mostly cloudy, with a low around 22.
Monday
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:
1:21 pm EST Dec 1, 2025
Forecast Valid:
5pm EST Dec 1, 2025-6pm EST Dec 8, 2025
 
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