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

57°F

14°C

Humidity 90%
Wind Speed N 15 G 24 mph
Barometer 29.72 in (1006.2 mb)
Dewpoint 54°F (12°C)
Visibility 10.00 mi
Last update 12 Oct 6:56 am EDT
Extended Forecast for

Holtsville NY

  • Columbus Day

    Columbus Day: A 30 percent chance of showers and thunderstorms before 8am. Mostly cloudy through mid morning, then gradual clearing, with a high near 70. North wind 7 to 11 mph, with gusts as high as 21 mph.

    High: 70 °F

    Chance
    T-storms then
    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 56. Light northwest wind.

    Low: 56 °F

    Mostly Clear

  • Tuesday

    Tuesday: Increasing clouds, with a high near 69. Calm wind becoming south 5 to 9 mph in the morning.

    High: 69 °F

    Increasing
    Clouds

  • Tuesday Night

    Tuesday Night: Mostly cloudy, then gradually becoming mostly clear, with a steady temperature around 65. Southwest wind around 10 mph, with gusts as high as 21 mph.

    Low: 65 °F

    Decreasing
    Clouds

  • Wednesday

    Wednesday: Sunny, with a high near 75. West wind 8 to 10 mph.

    High: 75 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 56.

    Low: 56 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 65.

    High: 65 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: A 50 percent chance of showers after 2am. Partly cloudy, with a low around 53.

    Low: 53 °F

    Partly Cloudy
    then Chance
    Showers

  • Friday

    Friday: Showers, mainly after 8am. High near 68. Chance of precipitation is 80%.

    High: 68 °F

    Showers

Detailed Forecast

Columbus Day
A 30 percent chance of showers and thunderstorms before 8am. Mostly cloudy through mid morning, then gradual clearing, with a high near 70. North wind 7 to 11 mph, with gusts as high as 21 mph.
Tonight
Mostly clear, with a low around 56. Light northwest wind.
Tuesday
Increasing clouds, with a high near 69. Calm wind becoming south 5 to 9 mph in the morning.
Tuesday Night
Mostly cloudy, then gradually becoming mostly clear, with a steady temperature around 65. Southwest wind around 10 mph, with gusts as high as 21 mph.
Wednesday
Sunny, with a high near 75. West wind 8 to 10 mph.
Wednesday Night
Mostly cloudy, with a low around 56.
Thursday
Mostly sunny, with a high near 65.
Thursday Night
A 50 percent chance of showers after 2am. Partly cloudy, with a low around 53.
Friday
Showers, mainly after 8am. High near 68. Chance of precipitation is 80%.
Friday Night
Showers likely, mainly before 8pm. Mostly cloudy, with a low around 46. Chance of precipitation is 60%.
Saturday
Mostly sunny, with a high near 54. Breezy.
Saturday Night
Mostly clear, with a low around 39.
Sunday
Sunny, with a high near 55.
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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:
6:26 am EDT Oct 12, 2026
Forecast Valid:
7am EDT Oct 12, 2026-6pm EDT Oct 18, 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