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.

Mostly Cloudy

53°F

12°C

Humidity 72%
Wind Speed Calm
Barometer 29.87 in (1011.5 mb)
Dewpoint 44°F (7°C)
Visibility 10.00 mi
Last update 11 Nov 5:56 pm EST
Extended Forecast for

Holtsville NY

  • Tonight

    Tonight: Increasing clouds, with a low around 49. Calm wind becoming east around 5 mph after midnight.

    Low: 49 °F

    Increasing
    Clouds

  • Thursday

    Thursday: Showers, mainly after 1pm. High near 60. East wind 6 to 13 mph. Chance of precipitation is 90%. New precipitation amounts between a half and three quarters of an inch possible.

    High: 60 °F

    Chance
    Showers then
    Showers

  • Thursday Night

    Thursday Night: Rain, mainly after 1am. Low around 38. Northeast wind 9 to 13 mph, with gusts as high as 24 mph. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.

    Low: 38 °F

    Rain

  • Friday

    Friday: Rain. High near 48. North wind 13 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 48 °F

    Rain

  • Friday Night

    Friday Night: Rain likely, mainly before 10pm. Mostly cloudy, with a low around 34. North wind 7 to 9 mph. Chance of precipitation is 60%.

    Low: 34 °F

    Rain Likely
    then Slight
    Chance Rain

  • Saturday

    Saturday: Partly sunny, with a high near 48.

    High: 48 °F

    Partly Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 34.

    Low: 34 °F

    Partly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 51.

    High: 51 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 35.

    Low: 35 °F

    Partly Cloudy

Detailed Forecast

Tonight
Increasing clouds, with a low around 49. Calm wind becoming east around 5 mph after midnight.
Thursday
Showers, mainly after 1pm. High near 60. East wind 6 to 13 mph. Chance of precipitation is 90%. New precipitation amounts between a half and three quarters of an inch possible.
Thursday Night
Rain, mainly after 1am. Low around 38. Northeast wind 9 to 13 mph, with gusts as high as 24 mph. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.
Friday
Rain. High near 48. North wind 13 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.
Friday Night
Rain likely, mainly before 10pm. Mostly cloudy, with a low around 34. North wind 7 to 9 mph. Chance of precipitation is 60%.
Saturday
Partly sunny, with a high near 48.
Saturday Night
Partly cloudy, with a low around 34.
Sunday
Mostly sunny, with a high near 51.
Sunday Night
Partly cloudy, with a low around 35.
Monday
Sunny, with a high near 50.
Monday Night
Mostly clear, with a low around 34.
Tuesday
Sunny, with a high near 51.
Tuesday Night
Partly cloudy, with a low around 34.
Wednesday
Sunny, with a high near 54.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Holtsville NY
 40.82°N 73.02°W (Elev. 82 ft)
Last Update:
6:08 pm EST Nov 11, 2026
Forecast Valid:
6pm EST Nov 11, 2026-6pm EST Nov 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