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.

Light Rain

79°F

26°C

Humidity 88%
Wind Speed SW 7 mph
Barometer 30.06 in (1017.8 mb)
Dewpoint 75°F (24°C)
Visibility 10.00 mi
Heat Index83°F (28°C)
Last update 14 Jul 7:56 pm EDT
Extended Forecast for

Ronkonkoma NY

  • Tonight

    Tonight: Showers likely and possibly a thunderstorm before 11pm, then a chance of showers and thunderstorms between 11pm and 2am, then showers likely and possibly a thunderstorm after 2am. Patchy fog after 4am. Otherwise, mostly cloudy, with a low around 74. South wind 5 to 8 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    Low: 74 °F

    Showers
    Likely and
    Patchy Fog

  • Tuesday

    Tuesday: Showers likely and possibly a thunderstorm before 8am, then a chance of showers and thunderstorms, mainly between 8am and 11am. Patchy fog before 9am. Otherwise, mostly cloudy, then gradually becoming sunny, with a high near 83. Calm wind becoming south 5 to 8 mph in the afternoon. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    High: 83 °F

    Showers
    Likely and
    Patchy Fog
    then Slight
    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Patchy fog after 4am. Otherwise, partly cloudy, with a low around 74. Southwest wind 5 to 7 mph.

    Low: 74 °F

    Partly Cloudy
    then Patchy
    Fog

  • Wednesday

    Wednesday: A slight chance of showers, with thunderstorms also possible after 2pm. Patchy fog before 8am. Otherwise, partly sunny, with a high near 88. Light southwest wind becoming south 5 to 10 mph in the morning. Chance of precipitation is 20%.

    High: 88 °F

    Slight Chance
    T-storms and
    Patchy Fog

  • Wednesday Night

    Wednesday Night: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 76. Southwest wind 8 to 10 mph.

    Low: 76 °F

    Chance
    T-storms

  • Thursday

    Thursday: A chance of showers, with thunderstorms also possible after 2pm. Partly sunny, with a high near 89. Chance of precipitation is 30%.

    High: 89 °F

    Chance
    Showers then
    Chance
    T-storms

  • Thursday Night

    Thursday Night: A chance of thunderstorms before 8pm. Partly cloudy, with a low around 77. Chance of precipitation is 30%.

    Low: 77 °F

    Chance
    T-storms then
    Partly Cloudy

  • Friday

    Friday: A 30 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 90.

    High: 90 °F

    Mostly Sunny
    then Chance
    T-storms

  • Friday Night

    Friday Night: A 30 percent chance of showers and thunderstorms before 8pm. Mostly cloudy, with a low around 73.

    Low: 73 °F

    Chance
    T-storms then
    Partly Cloudy

Detailed Forecast

Tonight
Showers likely and possibly a thunderstorm before 11pm, then a chance of showers and thunderstorms between 11pm and 2am, then showers likely and possibly a thunderstorm after 2am. Patchy fog after 4am. Otherwise, mostly cloudy, with a low around 74. South wind 5 to 8 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Tuesday
Showers likely and possibly a thunderstorm before 8am, then a chance of showers and thunderstorms, mainly between 8am and 11am. Patchy fog before 9am. Otherwise, mostly cloudy, then gradually becoming sunny, with a high near 83. Calm wind becoming south 5 to 8 mph in the afternoon. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Tuesday Night
Patchy fog after 4am. Otherwise, partly cloudy, with a low around 74. Southwest wind 5 to 7 mph.
Wednesday
A slight chance of showers, with thunderstorms also possible after 2pm. Patchy fog before 8am. Otherwise, partly sunny, with a high near 88. Light southwest wind becoming south 5 to 10 mph in the morning. Chance of precipitation is 20%.
Wednesday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 76. Southwest wind 8 to 10 mph.
Thursday
A chance of showers, with thunderstorms also possible after 2pm. Partly sunny, with a high near 89. Chance of precipitation is 30%.
Thursday Night
A chance of thunderstorms before 8pm. Partly cloudy, with a low around 77. Chance of precipitation is 30%.
Friday
A 30 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 90.
Friday Night
A 30 percent chance of showers and thunderstorms before 8pm. Mostly cloudy, with a low around 73.
Saturday
Mostly sunny, with a high near 86.
Saturday Night
Partly cloudy, with a low around 72.
Sunday
A 30 percent chance of showers and thunderstorms. Partly sunny, with a high near 85.
Sunday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 73.
Monday
Mostly sunny, with a high near 86.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Ronkonkoma NY
 40.81°N 73.11°W (Elev. 98 ft)
Last Update:
2:29 pm EDT Jul 14, 2025
Forecast Valid:
8pm EDT Jul 14, 2025-6pm EDT Jul 21, 2025
 
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