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

34°F

1°C

Humidity 89%
Wind Speed Calm
Barometer 30.09 in (1018.9 mb)
Dewpoint 31°F (-1°C)
Visibility 10.00 mi
Last update 20 Apr 1:56 am EDT
Extended Forecast for

Lake Grove NY

Frost Advisory April 20, 02:22am until April 20, 08:00am
Freeze Warning April 21, 12:00am until April 21, 09:00am
Click here for hazard details and duration
Frost Advisory
Freeze Warning
  •  
    Frost Advisory April 20, 02:22am until April 20, 08:00am

    NOW until 8:00am Mon

    Frost Advisory

  • Overnight

    Low: 36 °F

    Areas Frost

  • Monday

    Monday: A 40 percent chance of showers after 8am. Areas of frost before 7am. Otherwise, partly sunny, with a high near 52. Light and variable wind becoming northwest 5 to 9 mph in the morning.

    High: 52 °F

    Chance
    Showers

  • Monday Night

    Monday Night: Partly cloudy, with a low around 31. Wind chill values between 25 and 30. Northwest wind 7 to 9 mph.

    Low: 31 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Sunny, with a high near 53. North wind 5 to 7 mph becoming southwest in the afternoon.

    High: 53 °F

    Sunny

  • Tuesday Night

    Tuesday Night: A 20 percent chance of showers after 2am. Increasing clouds, with a low around 41. South wind 6 to 8 mph.

    Low: 41 °F

    Partly Cloudy
    then Slight
    Chance
    Showers

  • Wednesday

    Wednesday: Cloudy, then gradually becoming mostly sunny, with a high near 57.

    High: 57 °F

    Decreasing
    Clouds

  • Wednesday Night

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

    Low: 44 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 64.

    High: 64 °F

    Mostly Sunny

Detailed Forecast

Overnight
Areas of frost after 5am. Otherwise, clear, with a low around 36. Light west wind.
Monday
A 40 percent chance of showers after 8am. Areas of frost before 7am. Otherwise, partly sunny, with a high near 52. Light and variable wind becoming northwest 5 to 9 mph in the morning.
Monday Night
Partly cloudy, with a low around 31. Wind chill values between 25 and 30. Northwest wind 7 to 9 mph.
Tuesday
Sunny, with a high near 53. North wind 5 to 7 mph becoming southwest in the afternoon.
Tuesday Night
A 20 percent chance of showers after 2am. Increasing clouds, with a low around 41. South wind 6 to 8 mph.
Wednesday
Cloudy, then gradually becoming mostly sunny, with a high near 57.
Wednesday Night
Partly cloudy, with a low around 44.
Thursday
Mostly sunny, with a high near 64.
Thursday Night
Partly cloudy, with a low around 46.
Friday
Mostly sunny, with a high near 62.
Friday Night
A 30 percent chance of showers. Partly cloudy, with a low around 44.
Saturday
A 40 percent chance of showers. Partly sunny, with a high near 59.
Saturday Night
A 50 percent chance of showers. Mostly cloudy, with a low around 44.
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:
Lake Grove NY
 40.85°N 73.1°W (Elev. 144 ft)
Last Update:
6:50 pm EDT Apr 19, 2026
Forecast Valid:
2am 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