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.

Fair

N/A

Humidity NA
Wind Speed SW 7 mph
Barometer 30.08 in
Dewpoint N/A
Visibility 10.00 mi
Last update 13 Jan 2:56 am EST
Extended Forecast for

Lake Ronkonkoma NY

  • Overnight

    Overnight: Mostly clear, with a low around 30. Wind chill values between 25 and 30. West wind around 8 mph.

    Low: 30 °F

    Mostly Clear

  • Tuesday

    Tuesday: Increasing clouds, with a high near 45. Wind chill values between 25 and 35 early. West wind 7 to 10 mph, with gusts as high as 21 mph.

    High: 45 °F

    Increasing
    Clouds

  • Tuesday Night

    Tuesday Night: A 20 percent chance of showers after 1am. Mostly cloudy, with a steady temperature around 41. Southwest wind 7 to 9 mph, with gusts as high as 20 mph.

    Low: 41 °F

    Mostly Cloudy
    then Slight
    Chance
    Showers

  • 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 50 percent chance of rain. Cloudy, with a low around 29. Calm wind becoming west around 5 mph after midnight.

    Low: 29 °F

    Chance Rain

  • Thursday

    Thursday: Partly sunny, with a temperature falling to around 29 by 5pm.

    High: 38 °F⇓

    Partly Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 16.

    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 26.

    Low: 26 °F

    Mostly Cloudy

Detailed Forecast

Overnight
Mostly clear, with a low around 30. Wind chill values between 25 and 30. West wind around 8 mph.
Tuesday
Increasing clouds, with a high near 45. Wind chill values between 25 and 35 early. West wind 7 to 10 mph, with gusts as high as 21 mph.
Tuesday Night
A 20 percent chance of showers after 1am. Mostly cloudy, with a steady temperature around 41. Southwest wind 7 to 9 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 50 percent chance of rain. Cloudy, with a low around 29. Calm wind becoming west around 5 mph after midnight.
Thursday
Partly sunny, with a temperature falling to around 29 by 5pm.
Thursday Night
Partly cloudy, with a low around 16.
Friday
Mostly sunny, with a high near 35.
Friday Night
Mostly cloudy, with a low around 26.
Saturday
Partly sunny, with a high near 40.
Saturday Night
Mostly cloudy, with a low around 27.
Sunday
Partly sunny, with a high near 37.
Sunday Night
Mostly cloudy, with a low around 22.
M.L.King Day
Partly 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 73.14°W (Elev. 98 ft)
Last Update:
1:18 am EST Jan 13, 2026
Forecast Valid:
3am EST Jan 13, 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