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.

Fog/Mist

67°F

19°C

Humidity 91%
Wind Speed SE 8 mph
Barometer 30.06 in (1017.8 mb)
Dewpoint 64°F (18°C)
Visibility 3.00 mi
Last update 17 Jun 12:56 pm EDT
Extended Forecast for

Smithtown NY

  • This Afternoon

    This Afternoon: Cloudy, with a high near 71. Southeast wind around 6 mph.

    High: 71 °F

    Cloudy

  • Tonight

    Tonight: A chance of showers, with thunderstorms also possible after 5am. Patchy fog. Otherwise, cloudy, with a low around 64. Southeast wind 3 to 5 mph. Chance of precipitation is 30%.

    Low: 64 °F

    Chance
    Showers and
    Patchy Fog

  • Wednesday

    Wednesday: A slight chance of showers and thunderstorms before 2pm, then a chance of showers between 2pm and 5pm, then showers likely and possibly a thunderstorm after 5pm. Mostly cloudy, with a high near 81. South wind 5 to 7 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    High: 81 °F

    Slight Chance
    T-storms then
    Showers
    Likely

  • Wednesday Night

    Wednesday Night: Showers and thunderstorms likely before 11pm, then a slight chance of showers between 11pm and 2am. Mostly cloudy, with a low around 67. South wind around 6 mph. Chance of precipitation is 60%.

    Low: 67 °F

    Showers
    Likely then
    Slight Chance
    Showers

  • Juneteenth

    Juneteenth: A 30 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 89. Southwest wind 7 to 14 mph.

    High: 89 °F

    Mostly Sunny
    then Chance
    T-storms

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 11pm. Partly cloudy, with a low around 67. Chance of precipitation is 30%.

    Low: 67 °F

    Chance
    T-storms then
    Partly Cloudy

  • Friday

    Friday: Sunny, with a high near 86.

    High: 86 °F

    Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 66.

    Low: 66 °F

    Mostly Clear

  • Saturday

    Saturday: Mostly sunny, with a high near 86.

    High: 86 °F

    Mostly Sunny

Detailed Forecast

This Afternoon
Cloudy, with a high near 71. Southeast wind around 6 mph.
Tonight
A chance of showers, with thunderstorms also possible after 5am. Patchy fog. Otherwise, cloudy, with a low around 64. Southeast wind 3 to 5 mph. Chance of precipitation is 30%.
Wednesday
A slight chance of showers and thunderstorms before 2pm, then a chance of showers between 2pm and 5pm, then showers likely and possibly a thunderstorm after 5pm. Mostly cloudy, with a high near 81. South wind 5 to 7 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Wednesday Night
Showers and thunderstorms likely before 11pm, then a slight chance of showers between 11pm and 2am. Mostly cloudy, with a low around 67. South wind around 6 mph. Chance of precipitation is 60%.
Juneteenth
A 30 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 89. Southwest wind 7 to 14 mph.
Thursday Night
A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 11pm. Partly cloudy, with a low around 67. Chance of precipitation is 30%.
Friday
Sunny, with a high near 86.
Friday Night
Mostly clear, with a low around 66.
Saturday
Mostly sunny, with a high near 86.
Saturday Night
Mostly cloudy, with a low around 68.
Sunday
Mostly sunny, with a high near 89.
Sunday Night
Partly cloudy, with a low around 70.
Monday
Mostly sunny, with a high near 91.
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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:
12:28 pm EDT Jun 17, 2025
Forecast Valid:
1pm EDT Jun 17, 2025-6pm EDT Jun 23, 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