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.

Overcast

62°F

17°C

Humidity 67%
Wind Speed E 10 mph
Barometer 30.22 in (1023.2 mb)
Dewpoint 51°F (11°C)
Visibility 10.00 mi
Last update 4 Oct 12:56 pm EDT
Extended Forecast for

Mount Sinai NY

  • This Afternoon

    This Afternoon: Showers, mainly after 2pm. High near 62. East wind around 11 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 62 °F

    Showers

  • Tonight

    Tonight: Showers likely, mainly before 10pm. Mostly cloudy, with a low around 56. Northeast wind 5 to 9 mph becoming north after midnight. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

    Low: 56 °F

    Showers
    Likely then
    Mostly Cloudy

  • Monday

    Monday: Mostly cloudy through mid morning, then gradual clearing, with a high near 66. West wind 8 to 18 mph.

    High: 66 °F

    Becoming
    Sunny

  • Monday Night

    Monday Night: Clear, with a low around 48. Northwest wind 15 to 17 mph.

    Low: 48 °F

    Clear

  • Tuesday

    Tuesday: Sunny, with a high near 60. West wind around 11 mph.

    High: 60 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Clear, with a low around 51.

    Low: 51 °F

    Clear

  • Wednesday

    Wednesday: Sunny, with a high near 64.

    High: 64 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 58.

    Low: 58 °F

    Mostly Clear

  • Thursday

    Thursday: Sunny, with a high near 69.

    High: 69 °F

    Sunny

Detailed Forecast

This Afternoon
Showers, mainly after 2pm. High near 62. East wind around 11 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.
Tonight
Showers likely, mainly before 10pm. Mostly cloudy, with a low around 56. Northeast wind 5 to 9 mph becoming north after midnight. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Monday
Mostly cloudy through mid morning, then gradual clearing, with a high near 66. West wind 8 to 18 mph.
Monday Night
Clear, with a low around 48. Northwest wind 15 to 17 mph.
Tuesday
Sunny, with a high near 60. West wind around 11 mph.
Tuesday Night
Clear, with a low around 51.
Wednesday
Sunny, with a high near 64.
Wednesday Night
Mostly clear, with a low around 58.
Thursday
Sunny, with a high near 69.
Thursday Night
Mostly clear, with a low around 57.
Friday
Sunny, with a high near 67.
Friday Night
Partly cloudy, with a low around 57.
Saturday
Mostly sunny, with a high near 65.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Mount Sinai NY
 40.95°N 73.02°W (Elev. 56 ft)
Last Update:
10:11 am EDT Oct 4, 2026
Forecast Valid:
1pm EDT Oct 4, 2026-6pm EDT Oct 10, 2026
 
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