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

65°F

18°C

Humidity 93%
Wind Speed N 3 mph
Barometer 30.05 in (1017.5 mb)
Dewpoint 63°F (17°C)
Visibility 10.00 mi
Last update 4 Aug 5:56 am EDT
Extended Forecast for

Smithtown NY

  • Today

    Today: Mostly sunny, with a high near 83. North wind around 6 mph becoming calm in the morning.

    High: 83 °F

    Mostly Sunny

  • Tonight

    Tonight: Mostly cloudy, with a low around 66. Southeast wind around 5 mph becoming calm in the evening.

    Low: 66 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Partly sunny, with a high near 83. Calm wind becoming south around 6 mph in the afternoon.

    High: 83 °F

    Partly Sunny

  • Wednesday Night

    Wednesday Night: A 20 percent chance of showers. Mostly cloudy, with a low around 71. South wind around 7 mph.

    Low: 71 °F

    Slight Chance
    Showers

  • Thursday

    Thursday: Mostly sunny, with a high near 88. Southwest wind 5 to 10 mph.

    High: 88 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 73.

    Low: 73 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 89.

    High: 89 °F

    Mostly Sunny

  • Friday Night

    Friday Night: A chance of showers between 8pm and 2am. Mostly cloudy, with a low around 72. Chance of precipitation is 30%.

    Low: 72 °F

    Chance
    Showers

  • Saturday

    Saturday: A 30 percent chance of showers after 2pm. Mostly sunny, with a high near 88.

    High: 88 °F

    Mostly Sunny
    then Chance
    Showers

Detailed Forecast

Today
Mostly sunny, with a high near 83. North wind around 6 mph becoming calm in the morning.
Tonight
Mostly cloudy, with a low around 66. Southeast wind around 5 mph becoming calm in the evening.
Wednesday
Partly sunny, with a high near 83. Calm wind becoming south around 6 mph in the afternoon.
Wednesday Night
A 20 percent chance of showers. Mostly cloudy, with a low around 71. South wind around 7 mph.
Thursday
Mostly sunny, with a high near 88. Southwest wind 5 to 10 mph.
Thursday Night
Partly cloudy, with a low around 73.
Friday
Mostly sunny, with a high near 89.
Friday Night
A chance of showers between 8pm and 2am. Mostly cloudy, with a low around 72. Chance of precipitation is 30%.
Saturday
A 30 percent chance of showers after 2pm. Mostly sunny, with a high near 88.
Saturday Night
A 30 percent chance of showers before 2am. Mostly cloudy, with a low around 72.
Sunday
Mostly sunny, with a high near 88.
Sunday Night
Partly cloudy, with a low around 73.
Monday
Sunny, with a high near 89.
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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:
2:53 am EDT Aug 4, 2026
Forecast Valid:
6am EDT Aug 4, 2026-6pm EDT Aug 10, 2026
 
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