National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hazardous Weather Conditions

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 Calm
Barometer 30.14 in (1020.6 mb)
Dewpoint 33°F (1°C)
Visibility 10.00 mi
Last update 20 Apr 7:56 am EDT
Extended Forecast for

Smithtown NY

Freeze Warning April 21, 12:00am until April 21, 09:00am
Click here for hazard details and duration
Freeze Warning

  • Today

    Today: A 30 percent chance of showers, mainly before 2pm. Partly sunny, with a high near 52. Calm wind becoming northwest 5 to 7 mph in the morning.

    High: 52 °F

    Chance
    Showers

  • Tonight

    Tonight: Mostly cloudy, then gradually becoming clear, with a low around 33. North wind around 8 mph.

    Low: 33 °F

    Decreasing
    Clouds

  • Tuesday

    Tuesday: Sunny, with a high near 53. North wind around 6 mph becoming southwest in the afternoon.

    High: 53 °F

    Sunny

  • Tuesday Night

    Tuesday Night: A 30 percent chance of showers after 2am. Increasing clouds, with a low around 40. South wind around 7 mph.

    Low: 40 °F

    Mostly Cloudy
    then Chance
    Showers

  • Wednesday

    Wednesday: A 30 percent chance of showers, mainly before 8am. Mostly cloudy, with a high near 58. South wind around 8 mph.

    High: 58 °F

    Chance
    Showers

  • Wednesday Night

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

    Low: 45 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 64.

    High: 64 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 46.

    Low: 46 °F

    Mostly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 62.

    High: 62 °F

    Mostly Sunny

Detailed Forecast

Today
A 30 percent chance of showers, mainly before 2pm. Partly sunny, with a high near 52. Calm wind becoming northwest 5 to 7 mph in the morning.
Tonight
Mostly cloudy, then gradually becoming clear, with a low around 33. North wind around 8 mph.
Tuesday
Sunny, with a high near 53. North wind around 6 mph becoming southwest in the afternoon.
Tuesday Night
A 30 percent chance of showers after 2am. Increasing clouds, with a low around 40. South wind around 7 mph.
Wednesday
A 30 percent chance of showers, mainly before 8am. Mostly cloudy, with a high near 58. South wind around 8 mph.
Wednesday Night
Mostly cloudy, with a low around 45.
Thursday
Mostly sunny, with a high near 64.
Thursday Night
Mostly cloudy, with a low around 46.
Friday
Mostly sunny, with a high near 62.
Friday Night
Partly cloudy, with a low around 44.
Saturday
A 30 percent chance of showers. Partly sunny, with a high near 58.
Saturday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 43.
Sunday
A 30 percent chance of showers. Mostly cloudy, with a high near 58.
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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:
6:13 am EDT Apr 20, 2026
Forecast Valid:
8am EDT Apr 20, 2026-6pm EDT Apr 26, 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