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

74°F

23°C

Humidity 71%
Wind Speed SW 6 mph
Barometer 29.93 in (1013.6 mb)
Dewpoint 64°F (18°C)
Visibility 10.00 mi
Last update 24 Aug 7:56 pm EDT
Extended Forecast for

Lake Ronkonkoma NY

  • Tonight

    Tonight: Mostly clear, with a low around 62. West wind around 5 mph.

    Low: 62 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 79. West wind 7 to 11 mph, with gusts as high as 21 mph.

    High: 79 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Patchy fog after 2am. Otherwise, mostly clear, with a low around 62. West wind 5 to 7 mph becoming northwest after midnight.

    Low: 62 °F

    Partly Cloudy
    then Patchy
    Fog

  • Wednesday

    Wednesday: Patchy fog before 8am. Otherwise, sunny, with a high near 79. North wind 6 to 8 mph becoming west in the afternoon.

    High: 79 °F

    Patchy Fog
    then Mostly
    Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 68. South wind 5 to 7 mph.

    Low: 68 °F

    Partly Cloudy

  • Thursday

    Thursday: A chance of showers, with thunderstorms also possible after 2pm. Partly sunny, with a high near 79. Chance of precipitation is 50%.

    High: 79 °F

    Chance
    Showers then
    Chance
    T-storms

  • Thursday Night

    Thursday Night: Showers likely and possibly a thunderstorm. Mostly cloudy, with a low around 68. Chance of precipitation is 70%.

    Low: 68 °F

    Showers
    Likely

  • Friday

    Friday: A chance of showers before 8am, then a chance of showers after 2pm. Partly sunny, with a high near 81. Chance of precipitation is 30%.

    High: 81 °F

    Chance
    Showers

  • Friday Night

    Friday Night: A 30 percent chance of showers before 8pm. Mostly cloudy, with a low around 66.

    Low: 66 °F

    Chance
    Showers then
    Partly Cloudy

Detailed Forecast

Tonight
Mostly clear, with a low around 62. West wind around 5 mph.
Tuesday
Sunny, with a high near 79. West wind 7 to 11 mph, with gusts as high as 21 mph.
Tuesday Night
Patchy fog after 2am. Otherwise, mostly clear, with a low around 62. West wind 5 to 7 mph becoming northwest after midnight.
Wednesday
Patchy fog before 8am. Otherwise, sunny, with a high near 79. North wind 6 to 8 mph becoming west in the afternoon.
Wednesday Night
Partly cloudy, with a low around 68. South wind 5 to 7 mph.
Thursday
A chance of showers, with thunderstorms also possible after 2pm. Partly sunny, with a high near 79. Chance of precipitation is 50%.
Thursday Night
Showers likely and possibly a thunderstorm. Mostly cloudy, with a low around 68. Chance of precipitation is 70%.
Friday
A chance of showers before 8am, then a chance of showers after 2pm. Partly sunny, with a high near 81. Chance of precipitation is 30%.
Friday Night
A 30 percent chance of showers before 8pm. Mostly cloudy, with a low around 66.
Saturday
Mostly sunny, with a high near 80.
Saturday Night
Partly cloudy, with a low around 64.
Sunday
Mostly sunny, with a high near 79.
Sunday Night
Partly cloudy, with a low around 67.
Monday
Mostly sunny, with a high near 82.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Lake Ronkonkoma NY
 40.83°N 73.11°W (Elev. 98 ft)
Last Update:
2:49 pm EDT Aug 24, 2026
Forecast Valid:
8pm EDT Aug 24, 2026-6pm EDT Aug 31, 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