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

44°F

7°C

Humidity 58%
Wind Speed S 13 G 20 mph
Barometer 29.91 in
Dewpoint 30°F (-1°C)
Visibility 10.00 mi
Wind Chill38°F (3°C)
Last update 13 Jan 3:56 pm EST
Extended Forecast for

Holtsville NY

  • Tonight

    Tonight: A 20 percent chance of rain after 4am. Mostly cloudy, with a low around 38. Southwest wind 8 to 10 mph, with gusts as high as 23 mph.

    Low: 38 °F

    Mostly Cloudy
    then Slight
    Chance Rain

  • Wednesday

    Wednesday: A 20 percent chance of rain before 10am. Mostly cloudy, with a high near 46. Southwest wind 6 to 9 mph.

    High: 46 °F

    Slight Chance
    Rain then
    Mostly Cloudy

  • Wednesday Night

    Wednesday Night: A 40 percent chance of rain, mainly after 1am. Cloudy, with a low around 29. Calm wind becoming southwest around 6 mph after midnight.

    Low: 29 °F

    Chance Rain

  • Thursday

    Thursday: Cloudy, then gradually becoming mostly sunny, with a temperature rising to near 35 by 10am, then falling to around 28 during the remainder of the day. Wind chill values between 20 and 25. West wind 8 to 14 mph, with gusts as high as 24 mph.

    High: 35 °F⇓

    Decreasing
    Clouds

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 16. Northwest wind around 10 mph, with gusts as high as 23 mph.

    Low: 16 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 35.

    High: 35 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Mostly cloudy, with a low around 27.

    Low: 27 °F

    Mostly Cloudy

  • Saturday

    Saturday: Partly sunny, with a high near 41.

    High: 41 °F

    Partly Sunny

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around 26.

    Low: 26 °F

    Mostly Cloudy

Detailed Forecast

Tonight
A 20 percent chance of rain after 4am. Mostly cloudy, with a low around 38. Southwest wind 8 to 10 mph, with gusts as high as 23 mph.
Wednesday
A 20 percent chance of rain before 10am. Mostly cloudy, with a high near 46. Southwest wind 6 to 9 mph.
Wednesday Night
A 40 percent chance of rain, mainly after 1am. Cloudy, with a low around 29. Calm wind becoming southwest around 6 mph after midnight.
Thursday
Cloudy, then gradually becoming mostly sunny, with a temperature rising to near 35 by 10am, then falling to around 28 during the remainder of the day. Wind chill values between 20 and 25. West wind 8 to 14 mph, with gusts as high as 24 mph.
Thursday Night
Partly cloudy, with a low around 16. Northwest wind around 10 mph, with gusts as high as 23 mph.
Friday
Mostly sunny, with a high near 35.
Friday Night
Mostly cloudy, with a low around 27.
Saturday
Partly sunny, with a high near 41.
Saturday Night
Mostly cloudy, with a low around 26.
Sunday
Partly sunny, with a high near 33.
Sunday Night
Partly cloudy, with a low around 20.
M.L.King Day
Mostly sunny, with a high near 31.
Monday Night
Partly cloudy, with a low around 18.
Tuesday
Mostly sunny, with a high near 27.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Holtsville NY
 40.82°N 73.05°W (Elev. 112 ft)
Last Update:
12:35 pm EST Jan 13, 2026
Forecast Valid:
4pm EST Jan 13, 2026-6pm EST Jan 20, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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