National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hazardous Weather Conditions

Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

Mostly Cloudy

83°F

28°C

Humidity 79%
Wind Speed S 12 mph
Barometer 29.97 in (1014.6 mb)
Dewpoint 76°F (24°C)
Visibility 10.00 mi
Heat Index91°F (33°C)
Last update 16 Jul 6:56 pm EDT
Extended Forecast for

Lake Ronkonkoma NY

Heat Advisory July 16, 07:44pm until July 17, 10:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory July 16, 07:44pm until July 17, 10:00pm

    NOW until 10:00pm Thu

    Heat Advisory

  • Tonight

    Low: 75 °F

    Chance
    T-storms and
    Patchy Fog

  • Thursday

    Thursday: A 40 percent chance of showers and thunderstorms. Partly sunny, with a high near 90. Heat index values as high as 101. Southwest wind 8 to 13 mph.

    High: 90 °F

    Chance
    T-storms

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 72. Southwest wind 8 to 11 mph becoming west after midnight.

    Low: 72 °F

    Partly Cloudy

  • Friday

    Friday: Sunny, with a high near 87. Northwest wind 10 to 13 mph.

    High: 87 °F

    Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 67. North wind around 6 mph.

    Low: 67 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 84.

    High: 84 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: A chance of showers, with thunderstorms also possible after 2am. Mostly cloudy, with a low around 71. Chance of precipitation is 40%.

    Low: 71 °F

    Chance
    Showers then
    Chance
    T-storms

  • Sunday

    Sunday: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 83.

    High: 83 °F

    Chance
    T-storms

Detailed Forecast

Tonight
A 30 percent chance of showers and thunderstorms, mainly after 2am. Patchy fog after 11pm. Otherwise, mostly cloudy, with a low around 75. Southwest wind 6 to 8 mph.
Thursday
A 40 percent chance of showers and thunderstorms. Partly sunny, with a high near 90. Heat index values as high as 101. Southwest wind 8 to 13 mph.
Thursday Night
Partly cloudy, with a low around 72. Southwest wind 8 to 11 mph becoming west after midnight.
Friday
Sunny, with a high near 87. Northwest wind 10 to 13 mph.
Friday Night
Partly cloudy, with a low around 67. North wind around 6 mph.
Saturday
Mostly sunny, with a high near 84.
Saturday Night
A chance of showers, with thunderstorms also possible after 2am. Mostly cloudy, with a low around 71. Chance of precipitation is 40%.
Sunday
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 83.
Sunday Night
Mostly cloudy, with a low around 70.
Monday
Mostly sunny, with a high near 84.
Monday Night
Partly cloudy, with a low around 69.
Tuesday
Mostly sunny, with a high near 83.
Tuesday Night
Mostly cloudy, with a low around 71.
Wednesday
Partly sunny, with a high near 86.
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:
2:07 pm EDT Jul 16, 2025
Forecast Valid:
7pm EDT Jul 16, 2025-6pm EDT Jul 23, 2025
 
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