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.

Overcast

62°F

17°C

Humidity 80%
Wind Speed E 7 mph
Barometer 30.17 in (1021.7 mb)
Dewpoint 56°F (13°C)
Visibility 10.00 mi
Last update 15 Jun 10:56 am EDT
Extended Forecast for

Holtsville NY

  • Today

    Today: A 20 percent chance of light rain. Mostly cloudy, with a high near 68. East wind around 9 mph.

    High: 68 °F

    Slight Chance
    Light Rain

  • Tonight

    Tonight: A 20 percent chance of light rain. Mostly cloudy, with a low around 59. East wind around 6 mph.

    Low: 59 °F

    Slight Chance
    Light Rain

  • Monday

    Monday: Mostly cloudy, with a high near 70. East wind 7 to 10 mph.

    High: 70 °F

    Mostly Cloudy

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 59. East wind 3 to 6 mph.

    Low: 59 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: Mostly cloudy, with a high near 73. East wind 6 to 9 mph.

    High: 73 °F

    Mostly Cloudy

  • Tuesday Night

    Tuesday Night: A 30 percent chance of showers. Mostly cloudy, with a low around 62.

    Low: 62 °F

    Chance
    Showers

  • Wednesday

    Wednesday: Mostly cloudy, with a high near 79.

    High: 79 °F

    Mostly Cloudy

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 67.

    Low: 67 °F

    Mostly Cloudy

  • Juneteenth

    Juneteenth: A 30 percent chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 86.

    High: 86 °F

    Partly Sunny
    then Chance
    T-storms

Detailed Forecast

Today
A 20 percent chance of light rain. Mostly cloudy, with a high near 68. East wind around 9 mph.
Tonight
A 20 percent chance of light rain. Mostly cloudy, with a low around 59. East wind around 6 mph.
Monday
Mostly cloudy, with a high near 70. East wind 7 to 10 mph.
Monday Night
Mostly cloudy, with a low around 59. East wind 3 to 6 mph.
Tuesday
Mostly cloudy, with a high near 73. East wind 6 to 9 mph.
Tuesday Night
A 30 percent chance of showers. Mostly cloudy, with a low around 62.
Wednesday
Mostly cloudy, with a high near 79.
Wednesday Night
Mostly cloudy, with a low around 67.
Juneteenth
A 30 percent chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 86.
Thursday Night
A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 2am. Mostly cloudy, with a low around 67. Chance of precipitation is 30%.
Friday
Mostly sunny, with a high near 82.
Friday Night
Mostly clear, with a low around 64.
Saturday
Mostly sunny, with a high near 82.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Holtsville NY
 40.82°N 73.05°W (Elev. 112 ft)
Last Update:
10:18 am EDT Jun 15, 2025
Forecast Valid:
11am EDT Jun 15, 2025-6pm EDT Jun 21, 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