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 65%
Wind Speed SW 17 G 24 mph
Barometer 29.68 in (1005.2 mb)
Dewpoint 33°F (1°C)
Visibility 10.00 mi
Wind Chill36°F (2°C)
Last update 10 Dec 9:56 am EST
Extended Forecast for

Smithtown NY

  • Today

    Today: Rain likely, mainly after 4pm. Mostly cloudy, with a high near 47. Southwest wind 14 to 17 mph, with gusts as high as 33 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 47 °F

    Mostly Cloudy
    then Rain
    Likely

  • Tonight

    Tonight: Rain, mainly before 10pm. Low around 29. Southwest wind 9 to 13 mph, with gusts as high as 26 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

    Low: 29 °F

    Rain then
    Mostly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 37. Wind chill values between 20 and 25. West wind 15 to 18 mph, with gusts as high as 34 mph.

    High: 37 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 24. Wind chill values between 10 and 20. West wind 14 to 17 mph, with gusts as high as 33 mph.

    Low: 24 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 35. West wind 11 to 15 mph, with gusts as high as 26 mph.

    High: 35 °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

    Partly Cloudy
    then Chance
    Snow

  • Saturday

    Saturday: Partly sunny, with a high near 40.

    High: 40 °F

    Partly Sunny

  • Saturday Night

    Saturday Night: A 30 percent chance of snow after 1am. Mostly cloudy, with a low around 26.

    Low: 26 °F

    Mostly Cloudy
    then Chance
    Snow

  • Sunday

    Sunday: A 30 percent chance of snow before 1pm. Mostly cloudy, with a high near 35.

    High: 35 °F

    Chance Snow

Detailed Forecast

Today
Rain likely, mainly after 4pm. Mostly cloudy, with a high near 47. Southwest wind 14 to 17 mph, with gusts as high as 33 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.
Tonight
Rain, mainly before 10pm. Low around 29. Southwest wind 9 to 13 mph, with gusts as high as 26 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.
Thursday
Mostly sunny, with a high near 37. Wind chill values between 20 and 25. West wind 15 to 18 mph, with gusts as high as 34 mph.
Thursday Night
Partly cloudy, with a low around 24. Wind chill values between 10 and 20. West wind 14 to 17 mph, with gusts as high as 33 mph.
Friday
Mostly sunny, with a high near 35. West wind 11 to 15 mph, with gusts as high as 26 mph.
Friday Night
A 30 percent chance of snow after 1am. Mostly cloudy, with a low around 25.
Saturday
Partly sunny, with a high near 40.
Saturday Night
A 30 percent chance of snow after 1am. Mostly cloudy, with a low around 26.
Sunday
A 30 percent chance of snow before 1pm. Mostly cloudy, with a high near 35.
Sunday Night
Partly cloudy, with a low around 18.
Monday
Sunny, with a high near 31.
Monday Night
Mostly cloudy, with a low around 19.
Tuesday
Partly sunny, with a high near 33.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Smithtown NY
 40.86°N 73.19°W (Elev. 98 ft)
Last Update:
2:32 am EST Dec 10, 2025
Forecast Valid:
10am EST Dec 10, 2025-6pm EST Dec 16, 2025
 
Forecast Discussion
 
Get as KML Get as XML

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