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.

Partly Cloudy

76°F

24°C

Humidity 67%
Wind Speed S 15 G 25 mph
Barometer 30.14 in (1020.7 mb)
Dewpoint 64°F (18°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 7 Oct 12:56 pm EDT
Extended Forecast for

Mount Sinai NY

  • This Afternoon

    This Afternoon: Mostly sunny, with a high near 77. South wind 11 to 13 mph.

    High: 77 °F

    Mostly Sunny

  • Tonight

    Tonight: A chance of showers, then showers likely and possibly a thunderstorm after 4am. Mostly cloudy, with a low around 61. South wind around 14 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    Low: 61 °F

    Slight Chance
    Showers then
    Showers
    Likely

  • Wednesday

    Wednesday: Showers and possibly a thunderstorm. High near 71. Southwest wind 11 to 13 mph becoming north in the afternoon. Chance of precipitation is 90%. New precipitation amounts between a quarter and half of an inch possible.

    High: 71 °F

    Showers then
    Chance
    Showers

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 48. North wind around 15 mph.

    Low: 48 °F

    Mostly Clear

  • Thursday

    Thursday: Sunny, with a high near 60. North wind 10 to 14 mph.

    High: 60 °F

    Sunny

  • Thursday Night

    Thursday Night: Clear, with a low around 46.

    Low: 46 °F

    Clear

  • Friday

    Friday: Sunny, with a high near 63.

    High: 63 °F

    Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 51.

    Low: 51 °F

    Mostly Clear

  • Saturday

    Saturday: Mostly sunny, with a high near 66.

    High: 66 °F

    Mostly Sunny

Detailed Forecast

This Afternoon
Mostly sunny, with a high near 77. South wind 11 to 13 mph.
Tonight
A chance of showers, then showers likely and possibly a thunderstorm after 4am. Mostly cloudy, with a low around 61. South wind around 14 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Wednesday
Showers and possibly a thunderstorm. High near 71. Southwest wind 11 to 13 mph becoming north in the afternoon. Chance of precipitation is 90%. New precipitation amounts between a quarter and half of an inch possible.
Wednesday Night
Mostly clear, with a low around 48. North wind around 15 mph.
Thursday
Sunny, with a high near 60. North wind 10 to 14 mph.
Thursday Night
Clear, with a low around 46.
Friday
Sunny, with a high near 63.
Friday Night
Mostly clear, with a low around 51.
Saturday
Mostly sunny, with a high near 66.
Saturday Night
Mostly cloudy, with a low around 54.
Sunday
Partly sunny, with a high near 66.
Sunday Night
A 30 percent chance of showers. Mostly cloudy, with a low around 53.
Columbus Day
Mostly sunny, with a high near 66.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Mount Sinai NY
 40.95°N 73.02°W (Elev. 56 ft)
Last Update:
6:26 am EDT Oct 7, 2025
Forecast Valid:
1pm EDT Oct 7, 2025-6pm EDT Oct 13, 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