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

81°F

27°C

Humidity 51%
Wind Speed SW 12 mph
Barometer 30.09 in (1018.9 mb)
Dewpoint 61°F (16°C)
Visibility 10.00 mi
Heat Index82°F (28°C)
Last update 21 Jun 5:56 pm EDT
Extended Forecast for

Lake Ronkonkoma NY

Extreme Heat Watch June 23, 12:00pm until June 24, 08:00pm
Heat Advisory June 22, 12:00pm until June 22, 08:00pm
Click here for hazard details and duration
Extreme Heat Watch
Heat Advisory

  • Tonight

    Tonight: Partly cloudy, with a low around 70. Southwest wind 6 to 9 mph.

    Low: 70 °F

    Partly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 91. Heat index values as high as 95. Southwest wind 9 to 14 mph.

    High: 91 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 74. West wind 6 to 9 mph.

    Low: 74 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 93. Heat index values as high as 99. Northwest wind 5 to 8 mph becoming south in the afternoon.

    High: 93 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 72. South wind 3 to 6 mph.

    Low: 72 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 95.

    High: 95 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 74.

    Low: 74 °F

    Mostly Clear

  • Wednesday

    Wednesday: Mostly sunny, with a high near 90.

    High: 90 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 67.

    Low: 67 °F

    Mostly Cloudy

Detailed Forecast

Tonight
Partly cloudy, with a low around 70. Southwest wind 6 to 9 mph.
Sunday
Mostly sunny, with a high near 91. Heat index values as high as 95. Southwest wind 9 to 14 mph.
Sunday Night
Mostly clear, with a low around 74. West wind 6 to 9 mph.
Monday
Sunny, with a high near 93. Heat index values as high as 99. Northwest wind 5 to 8 mph becoming south in the afternoon.
Monday Night
Mostly clear, with a low around 72. South wind 3 to 6 mph.
Tuesday
Sunny, with a high near 95.
Tuesday Night
Mostly clear, with a low around 74.
Wednesday
Mostly sunny, with a high near 90.
Wednesday Night
Mostly cloudy, with a low around 67.
Thursday
Partly sunny, with a high near 80.
Thursday Night
A 30 percent chance of showers. Mostly cloudy, with a low around 65.
Friday
A 30 percent chance of showers. Partly sunny, with a high near 77.
Friday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 65.
Saturday
A 30 percent chance of showers. Partly sunny, with a high near 79.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Lake Ronkonkoma NY
 40.83°N 73.11°W (Elev. 98 ft)
Last Update:
3:25 pm EDT Jun 21, 2025
Forecast Valid:
5pm EDT Jun 21, 2025-6pm EDT Jun 28, 2025
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

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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