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.

Partly Cloudy

77°F

25°C

Humidity 40%
Wind Speed Calm
Barometer 30.08 in (1018.5 mb)
Dewpoint 51°F (11°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 25 Jun 9:56 am EDT
Extended Forecast for

Lake Ronkonkoma NY

  • Today

    Today: Mostly sunny, with a high near 83. Light south wind increasing to 5 to 9 mph in the afternoon.

    High: 83 °F

    Mostly Sunny

  • Tonight

    Tonight: Showers likely and possibly a thunderstorm after 2am. Increasing clouds, with a low around 65. South wind 7 to 9 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 65 °F

    Partly Cloudy
    then Showers
    Likely

  • Friday

    Friday: Showers likely and possibly a thunderstorm before 8am, then a chance of showers between 8am and 11am. Partly sunny, with a high near 81. Southwest wind 7 to 9 mph. Chance of precipitation is 60%.

    High: 81 °F

    Showers
    Likely then
    Partly Sunny

  • Friday Night

    Friday Night: A 40 percent chance of showers after 2am. Mostly cloudy, with a low around 66. Southwest wind around 5 mph becoming calm in the evening.

    Low: 66 °F

    Mostly Cloudy
    then Chance
    Showers

  • Saturday

    Saturday: Showers likely, mainly between 8am and 2pm. Mostly cloudy, with a high near 77. Calm wind becoming east around 6 mph in the afternoon. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 77 °F

    Showers
    Likely

  • Saturday Night

    Saturday Night: A 30 percent chance of showers before 8pm. Mostly cloudy, with a low around 64.

    Low: 64 °F

    Chance
    Showers then
    Mostly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 86.

    High: 86 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 66.

    Low: 66 °F

    Partly Cloudy

  • Monday

    Monday: Mostly sunny, with a high near 88.

    High: 88 °F

    Mostly Sunny

Detailed Forecast

Today
Mostly sunny, with a high near 83. Light south wind increasing to 5 to 9 mph in the afternoon.
Tonight
Showers likely and possibly a thunderstorm after 2am. Increasing clouds, with a low around 65. South wind 7 to 9 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Friday
Showers likely and possibly a thunderstorm before 8am, then a chance of showers between 8am and 11am. Partly sunny, with a high near 81. Southwest wind 7 to 9 mph. Chance of precipitation is 60%.
Friday Night
A 40 percent chance of showers after 2am. Mostly cloudy, with a low around 66. Southwest wind around 5 mph becoming calm in the evening.
Saturday
Showers likely, mainly between 8am and 2pm. Mostly cloudy, with a high near 77. Calm wind becoming east around 6 mph in the afternoon. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.
Saturday Night
A 30 percent chance of showers before 8pm. Mostly cloudy, with a low around 64.
Sunday
Mostly sunny, with a high near 86.
Sunday Night
Partly cloudy, with a low around 66.
Monday
Mostly sunny, with a high near 88.
Monday Night
Partly cloudy, with a low around 68.
Tuesday
Mostly sunny, with a high near 90.
Tuesday Night
A 30 percent chance of showers. Partly cloudy, with a low around 70.
Wednesday
Mostly sunny, with a high near 92.
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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:
2:24 am EDT Jun 25, 2026
Forecast Valid:
10am EDT Jun 25, 2026-6pm EDT Jul 1, 2026
 
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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