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.

Light Rain

60°F

16°C

Humidity 80%
Wind Speed E 10 mph
Barometer 30.33 in (1027.0 mb)
Dewpoint 54°F (12°C)
Visibility 10.00 mi
Last update 11 Oct 10:56 am EDT
Extended Forecast for

Holtsville NY

  • Today

    Today: Rain, mainly after noon. High near 64. East wind 11 to 15 mph. Chance of precipitation is 100%. New precipitation amounts between a quarter and half of an inch possible.

    High: 64 °F

    Rain

  • Tonight

    Tonight: Rain and possibly a thunderstorm before 2am, then a chance of rain and thunderstorms, mainly between 2am and 5am. Low around 55. Northeast wind 9 to 14 mph, with gusts as high as 25 mph. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.

    Low: 55 °F

    Rain then
    Rain Likely

  • Columbus Day

    Columbus Day: A 40 percent chance of showers before 11am. Cloudy through mid morning, then gradual clearing, with a high near 68. North wind 9 to 13 mph.

    High: 68 °F

    Chance
    Showers then
    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 54. Light north wind.

    Low: 54 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 67. Light and variable wind becoming south 5 to 9 mph in the morning.

    High: 67 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 59.

    Low: 59 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Sunny, with a high near 72.

    High: 72 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 50.

    Low: 50 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny, with a high near 63.

    High: 63 °F

    Mostly Sunny

Detailed Forecast

Today
Rain, mainly after noon. High near 64. East wind 11 to 15 mph. Chance of precipitation is 100%. New precipitation amounts between a quarter and half of an inch possible.
Tonight
Rain and possibly a thunderstorm before 2am, then a chance of rain and thunderstorms, mainly between 2am and 5am. Low around 55. Northeast wind 9 to 14 mph, with gusts as high as 25 mph. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.
Columbus Day
A 40 percent chance of showers before 11am. Cloudy through mid morning, then gradual clearing, with a high near 68. North wind 9 to 13 mph.
Monday Night
Mostly clear, with a low around 54. Light north wind.
Tuesday
Mostly sunny, with a high near 67. Light and variable wind becoming south 5 to 9 mph in the morning.
Tuesday Night
Partly cloudy, with a low around 59.
Wednesday
Sunny, with a high near 72.
Wednesday Night
Mostly clear, with a low around 50.
Thursday
Mostly sunny, with a high near 63.
Thursday Night
Partly cloudy, with a low around 48.
Friday
A 50 percent chance of showers. Mostly cloudy, with a high near 64.
Friday Night
A 50 percent chance of showers. Mostly cloudy, with a low around 48.
Saturday
A 30 percent chance of showers. Partly sunny, with a high near 59.
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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:
11:12 am EDT Oct 11, 2026
Forecast Valid:
11am EDT Oct 11, 2026-6pm EDT Oct 17, 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