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.

A Few Clouds

59°F

15°C

Humidity 83%
Wind Speed Calm
Barometer 30.21 in (1022.9 mb)
Dewpoint 54°F (12°C)
Visibility 10.00 mi
Last update 4 Oct 7:56 am EDT
Extended Forecast for

Mount Sinai NY

  • Today

    Today: Sunny, with a high near 79. West wind around 6 mph.

    High: 79 °F

    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 60. Light and variable wind.

    Low: 60 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 80. Calm wind becoming south around 6 mph in the afternoon.

    High: 80 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 60. Southwest wind around 6 mph.

    Low: 60 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 78. Southwest wind 3 to 7 mph.

    High: 78 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 61.

    Low: 61 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 76.

    High: 76 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Showers likely, mainly after 2am. Mostly cloudy, with a low around 59. Chance of precipitation is 70%.

    Low: 59 °F

    Chance
    Showers then
    Showers
    Likely

  • Wednesday

    Wednesday: Showers likely, mainly before 2pm. Mostly cloudy, with a high near 70. Chance of precipitation is 70%.

    High: 70 °F

    Showers
    Likely

Detailed Forecast

Today
Sunny, with a high near 79. West wind around 6 mph.
Tonight
Mostly clear, with a low around 60. Light and variable wind.
Sunday
Sunny, with a high near 80. Calm wind becoming south around 6 mph in the afternoon.
Sunday Night
Mostly clear, with a low around 60. Southwest wind around 6 mph.
Monday
Sunny, with a high near 78. Southwest wind 3 to 7 mph.
Monday Night
Mostly clear, with a low around 61.
Tuesday
Mostly sunny, with a high near 76.
Tuesday Night
Showers likely, mainly after 2am. Mostly cloudy, with a low around 59. Chance of precipitation is 70%.
Wednesday
Showers likely, mainly before 2pm. Mostly cloudy, with a high near 70. Chance of precipitation is 70%.
Wednesday Night
A 30 percent chance of showers before 8pm. Partly cloudy, with a low around 48.
Thursday
Sunny, with a high near 61.
Thursday Night
Mostly clear, with a low around 48.
Friday
Mostly sunny, with a high near 65.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Mount Sinai NY
 40.93°N 73.03°W (Elev. 151 ft)
Last Update:
1:43 am EDT Oct 4, 2025
Forecast Valid:
8am EDT Oct 4, 2025-6pm EDT Oct 10, 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