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.

A Few Clouds

39°F

4°C

Humidity 46%
Wind Speed SW 14 mph
Barometer 30.09 in
Dewpoint 20°F (-7°C)
Visibility 10.00 mi
Wind Chill31°F (-1°C)
Last update 12 Jan 4:56 pm EST
Extended Forecast for

Lake Ronkonkoma NY

  • Tonight

    Tonight: Mostly clear, with a low around 30. West wind 6 to 9 mph, with gusts as high as 20 mph.

    Low: 30 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 45. Wind chill values between 25 and 35 early. West wind 6 to 9 mph.

    High: 45 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a steady temperature around 40. Southwest wind around 8 mph, with gusts as high as 20 mph.

    Low: 40 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: A 20 percent chance of showers before 1pm. Cloudy, with a high near 47. Southwest wind 6 to 8 mph.

    High: 47 °F

    Slight Chance
    Showers

  • Wednesday Night

    Wednesday Night: A 40 percent chance of showers, mainly after 1am. Cloudy, with a low around 31. Calm wind.

    Low: 31 °F

    Chance
    Showers

  • Thursday

    Thursday: A 30 percent chance of rain before 1pm. Mostly cloudy, with a high near 42.

    High: 42 °F

    Chance Rain

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 19.

    Low: 19 °F

    Mostly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 33.

    High: 33 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Mostly cloudy, with a low around 25.

    Low: 25 °F

    Mostly Cloudy

Detailed Forecast

Tonight
Mostly clear, with a low around 30. West wind 6 to 9 mph, with gusts as high as 20 mph.
Tuesday
Sunny, with a high near 45. Wind chill values between 25 and 35 early. West wind 6 to 9 mph.
Tuesday Night
Mostly cloudy, with a steady temperature around 40. Southwest wind around 8 mph, with gusts as high as 20 mph.
Wednesday
A 20 percent chance of showers before 1pm. Cloudy, with a high near 47. Southwest wind 6 to 8 mph.
Wednesday Night
A 40 percent chance of showers, mainly after 1am. Cloudy, with a low around 31. Calm wind.
Thursday
A 30 percent chance of rain before 1pm. Mostly cloudy, with a high near 42.
Thursday Night
Mostly cloudy, with a low around 19.
Friday
Mostly sunny, with a high near 33.
Friday Night
Mostly cloudy, with a low around 25.
Saturday
Mostly sunny, with a high near 40.
Saturday Night
Mostly cloudy, with a low around 28.
Sunday
A 30 percent chance of rain. Partly sunny, with a high near 37.
Sunday Night
Partly cloudy, with a low around 19.
M.L.King Day
Mostly sunny, with a high near 32.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Lake Ronkonkoma NY
 40.83°N 73.11°W (Elev. 98 ft)
Last Update:
12:48 pm EST Jan 12, 2026
Forecast Valid:
5pm EST Jan 12, 2026-6pm EST Jan 19, 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