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

49°F

9°C

Humidity 93%
Wind Speed Calm
Barometer 30.19 in (1022.4 mb)
Dewpoint 47°F (8°C)
Visibility 10.00 mi
Last update 3 Nov 6:56 am EST
Extended Forecast for

Smithtown NY

  • Today

    Today: A 50 percent chance of rain, mainly after 1pm. Mostly cloudy, with a high near 61. Light south wind increasing to 5 to 9 mph in the morning.

    High: 61 °F

    Slight Chance
    Rain then
    Chance Rain

  • Tonight

    Tonight: A 20 percent chance of rain before 10pm. Mostly cloudy during the early evening, then gradual clearing, with a low around 46. Southwest wind 9 to 17 mph becoming northwest after midnight. Winds could gust as high as 29 mph.

    Low: 46 °F

    Slight Chance
    Rain then
    Clear

  • Tuesday

    Tuesday: Sunny, with a high near 59. West wind 15 to 18 mph, with gusts as high as 29 mph.

    High: 59 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 44. West wind 6 to 8 mph.

    Low: 44 °F

    Mostly Clear

  • Wednesday

    Wednesday: Mostly sunny, with a high near 62. Southwest wind 6 to 14 mph.

    High: 62 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 45.

    Low: 45 °F

    Mostly Cloudy

  • Thursday

    Thursday: Sunny, with a high near 56.

    High: 56 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 39.

    Low: 39 °F

    Mostly Clear

  • Friday

    Friday: Partly sunny, with a high near 60.

    High: 60 °F

    Partly Sunny

Detailed Forecast

Today
A 50 percent chance of rain, mainly after 1pm. Mostly cloudy, with a high near 61. Light south wind increasing to 5 to 9 mph in the morning.
Tonight
A 20 percent chance of rain before 10pm. Mostly cloudy during the early evening, then gradual clearing, with a low around 46. Southwest wind 9 to 17 mph becoming northwest after midnight. Winds could gust as high as 29 mph.
Tuesday
Sunny, with a high near 59. West wind 15 to 18 mph, with gusts as high as 29 mph.
Tuesday Night
Mostly clear, with a low around 44. West wind 6 to 8 mph.
Wednesday
Mostly sunny, with a high near 62. Southwest wind 6 to 14 mph.
Wednesday Night
Mostly cloudy, with a low around 45.
Thursday
Sunny, with a high near 56.
Thursday Night
Mostly clear, with a low around 39.
Friday
Partly sunny, with a high near 60.
Friday Night
Rain likely, mainly after 1am. Mostly cloudy, with a low around 50. Chance of precipitation is 60%.
Saturday
Partly sunny, with a high near 61.
Saturday Night
Mostly cloudy, with a low around 43.
Sunday
A 30 percent chance of rain. Partly sunny, with a high near 56.
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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:
1:07 am EST Nov 3, 2025
Forecast Valid:
7am EST Nov 3, 2025-6pm EST Nov 9, 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