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.

Overcast

74°F

23°C

Humidity 85%
Wind Speed SW 12 mph
Barometer 30.06 in (1017.9 mb)
Dewpoint 69°F (21°C)
Visibility 10.00 mi
Last update 30 Aug 6:56 pm EDT
Extended Forecast for

Lake Ronkonkoma NY

  • Tonight

    Tonight: A chance of showers and thunderstorms between 8pm and 2am, then a slight chance of showers. Mostly cloudy, with a low around 66. Southwest wind 5 to 10 mph becoming light and variable after midnight. Chance of precipitation is 40%.

    Low: 66 °F

    Chance
    Showers

  • Monday

    Monday: A 20 percent chance of showers between 2pm and 5pm. Patchy fog between 7am and 8am. Otherwise, partly sunny, with a high near 79. Light and variable wind becoming southeast around 6 mph in the morning.

    High: 79 °F

    Slight Chance
    Showers and
    Patchy Fog

  • Monday Night

    Monday Night: A 40 percent chance of showers, mainly after 2am. Increasing clouds, with a low around 66. South wind around 5 mph becoming calm in the evening.

    Low: 66 °F

    Chance
    Showers

  • Tuesday

    Tuesday: A chance of showers before 8am, then showers likely and possibly a thunderstorm after 2pm. Mostly cloudy, with a high near 82. Southwest wind 5 to 8 mph. Chance of precipitation is 60%. New rainfall amounts between a quarter and half of an inch possible.

    High: 82 °F

    Chance
    Showers then
    Showers
    Likely

  • Tuesday Night

    Tuesday Night: Showers and thunderstorms likely before 11pm, then a chance of showers between 11pm and 2am. Mostly cloudy, with a low around 66. East wind 3 to 6 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    Low: 66 °F

    Showers
    Likely

  • Wednesday

    Wednesday: A 50 percent chance of showers after 2pm. Mostly cloudy, with a high near 79.

    High: 79 °F

    Mostly Cloudy
    then Chance
    Showers

  • Wednesday Night

    Wednesday Night: A chance of showers and thunderstorms before 8pm, then showers likely and possibly a thunderstorm between 8pm and 2am, then a chance of showers after 2am. Mostly cloudy, with a low around 67. Chance of precipitation is 60%.

    Low: 67 °F

    Showers
    Likely

  • Thursday

    Thursday: A chance of showers before 8am, then a chance of showers and thunderstorms after 2pm. Mostly cloudy, with a high near 83. Chance of precipitation is 40%.

    High: 83 °F

    Chance
    Showers then
    Chance
    T-storms

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 2am. Mostly cloudy, with a low around 66. Chance of precipitation is 40%.

    Low: 66 °F

    Chance
    T-storms then
    Chance
    Showers

Detailed Forecast

Tonight
A chance of showers and thunderstorms between 8pm and 2am, then a slight chance of showers. Mostly cloudy, with a low around 66. Southwest wind 5 to 10 mph becoming light and variable after midnight. Chance of precipitation is 40%.
Monday
A 20 percent chance of showers between 2pm and 5pm. Patchy fog between 7am and 8am. Otherwise, partly sunny, with a high near 79. Light and variable wind becoming southeast around 6 mph in the morning.
Monday Night
A 40 percent chance of showers, mainly after 2am. Increasing clouds, with a low around 66. South wind around 5 mph becoming calm in the evening.
Tuesday
A chance of showers before 8am, then showers likely and possibly a thunderstorm after 2pm. Mostly cloudy, with a high near 82. Southwest wind 5 to 8 mph. Chance of precipitation is 60%. New rainfall amounts between a quarter and half of an inch possible.
Tuesday Night
Showers and thunderstorms likely before 11pm, then a chance of showers between 11pm and 2am. Mostly cloudy, with a low around 66. East wind 3 to 6 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Wednesday
A 50 percent chance of showers after 2pm. Mostly cloudy, with a high near 79.
Wednesday Night
A chance of showers and thunderstorms before 8pm, then showers likely and possibly a thunderstorm between 8pm and 2am, then a chance of showers after 2am. Mostly cloudy, with a low around 67. Chance of precipitation is 60%.
Thursday
A chance of showers before 8am, then a chance of showers and thunderstorms after 2pm. Mostly cloudy, with a high near 83. Chance of precipitation is 40%.
Thursday Night
A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 2am. Mostly cloudy, with a low around 66. Chance of precipitation is 40%.
Friday
Mostly sunny, with a high near 80.
Friday Night
Partly cloudy, with a low around 62.
Saturday
Mostly sunny, with a high near 76.
Saturday Night
Partly cloudy, with a low around 60.
Sunday
Mostly sunny, with a high near 75.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Lake Ronkonkoma NY
 40.83°N 73.11°W (Elev. 98 ft)
Last Update:
3:05 pm EDT Aug 30, 2026
Forecast Valid:
7pm EDT Aug 30, 2026-6pm EDT Sep 6, 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