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.

Fair

31°F

-1°C

Humidity 92%
Wind Speed Calm
Barometer 30.10 in (1019.3 mb)
Dewpoint 29°F (-2°C)
Visibility 10.00 mi
Last update 20 Apr 4:56 am EDT
Extended Forecast for

Islip, Long Island Mac Arthur Airport NY

Frost Advisory April 20, 05:50am until April 20, 08:00am
Freeze Warning April 21, 12:00am until April 21, 09:00am
Click here for hazard details and duration
...
Freeze Warning
  •  
    Frost Advisory April 20, 05:50am until April 20, 08:00am

    NOW until 8:00am Mon

    Frost Advisory

  • Today

    High: 51 °F

    Chance
    Showers

  • Tonight

    Tonight: Mostly cloudy, then gradually becoming clear, with a low around 31. Wind chill values between 25 and 30. North wind around 7 mph.

    Low: 31 °F

    Decreasing
    Clouds

  • Tuesday

    Tuesday: Sunny, with a high near 51. North wind around 6 mph becoming south in the afternoon.

    High: 51 °F

    Sunny

  • Tuesday Night

    Tuesday Night: A 30 percent chance of showers after 2am. Increasing clouds, with a low around 39. South wind around 7 mph.

    Low: 39 °F

    Mostly Cloudy
    then Chance
    Showers

  • Wednesday

    Wednesday: A 30 percent chance of showers, mainly before 8am. Mostly cloudy, with a high near 56. South wind around 9 mph.

    High: 56 °F

    Chance
    Showers

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 44.

    Low: 44 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 62.

    High: 62 °F

    Mostly Sunny

  • Thursday Night

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

    Low: 45 °F

    Mostly Cloudy

Detailed Forecast

Today
A 30 percent chance of showers, mainly between 8am and 2pm. Increasing clouds, with a high near 51. Calm wind becoming northwest 5 to 7 mph in the morning.
Tonight
Mostly cloudy, then gradually becoming clear, with a low around 31. Wind chill values between 25 and 30. North wind around 7 mph.
Tuesday
Sunny, with a high near 51. North wind around 6 mph becoming south in the afternoon.
Tuesday Night
A 30 percent chance of showers after 2am. Increasing clouds, with a low around 39. South wind around 7 mph.
Wednesday
A 30 percent chance of showers, mainly before 8am. Mostly cloudy, with a high near 56. South wind around 9 mph.
Wednesday Night
Mostly cloudy, with a low around 44.
Thursday
Mostly sunny, with a high near 62.
Thursday Night
Mostly cloudy, with a low around 45.
Friday
Mostly sunny, with a high near 60.
Friday Night
Partly cloudy, with a low around 43.
Saturday
A 30 percent chance of showers. Partly sunny, with a high near 56.
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 57.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Islip, Long Island Mac Arthur Airport NY
 40.78°N 73.09°W (Elev. 49 ft)
Last Update:
2:20 am EDT Apr 20, 2026
Forecast Valid:
5am 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