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

66°F

19°C

Humidity 90%
Wind Speed SW 12 mph
Barometer 29.84 in (1010.3 mb)
Dewpoint 63°F (17°C)
Visibility 10.00 mi
Last update 14 Oct 1:56 am EDT
Extended Forecast for

Lake Ronkonkoma NY

  • Overnight

    Overnight: Mostly clear, with a steady temperature around 66. Southwest wind around 9 mph.

    Low: 66 °F

    Mostly Clear

  • Wednesday

    Wednesday: Mostly sunny, with a high near 78. West wind 8 to 10 mph.

    High: 78 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 52. North wind around 8 mph.

    Low: 52 °F

    Partly Cloudy

  • Thursday

    Thursday: Sunny, with a high near 63. North wind 5 to 9 mph.

    High: 63 °F

    Sunny

  • Thursday Night

    Thursday Night: Showers after 2am. Low around 50. Southeast wind 3 to 7 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

    Low: 50 °F

    Mostly Clear
    then Showers

  • Friday

    Friday: Showers. High near 71. Chance of precipitation is 90%. New precipitation amounts between a quarter and half of an inch possible.

    High: 71 °F

    Showers

  • Friday Night

    Friday Night: Showers likely before 2am. Cloudy, then gradually becoming partly cloudy, with a low around 43. Chance of precipitation is 70%.

    Low: 43 °F

    Showers
    Likely

  • Saturday

    Saturday: Sunny, with a high near 53. Breezy.

    High: 53 °F

    Mostly Sunny
    and Breezy
    then Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 38.

    Low: 38 °F

    Mostly Clear

Detailed Forecast

Overnight
Mostly clear, with a steady temperature around 66. Southwest wind around 9 mph.
Wednesday
Mostly sunny, with a high near 78. West wind 8 to 10 mph.
Wednesday Night
Partly cloudy, with a low around 52. North wind around 8 mph.
Thursday
Sunny, with a high near 63. North wind 5 to 9 mph.
Thursday Night
Showers after 2am. Low around 50. Southeast wind 3 to 7 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.
Friday
Showers. High near 71. Chance of precipitation is 90%. New precipitation amounts between a quarter and half of an inch possible.
Friday Night
Showers likely before 2am. Cloudy, then gradually becoming partly cloudy, with a low around 43. Chance of precipitation is 70%.
Saturday
Sunny, with a high near 53. Breezy.
Saturday Night
Mostly clear, with a low around 38.
Sunday
Sunny, with a high near 58.
Sunday Night
Mostly clear, with a low around 43.
Monday
Sunny, with a high near 63.
Monday Night
Mostly cloudy, with a low around 48.
Tuesday
Mostly sunny, with a high near 65.
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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:
1:52 am EDT Oct 14, 2026
Forecast Valid:
2am EDT Oct 14, 2026-6pm EDT Oct 20, 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