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.

Mostly Cloudy

57°F

14°C

Humidity 53%
Wind Speed NW 14 G 28 mph
Barometer 29.76 in (1007.6 mb)
Dewpoint 40°F (4°C)
Visibility 10.00 mi
Last update 9 Nov 12:56 pm EST
Extended Forecast for

Mount Sinai NY

  • This Afternoon

    This Afternoon: A 20 percent chance of rain before 4pm. Mostly sunny, with a high near 57. Northwest wind around 16 mph, with gusts as high as 31 mph.

    High: 57 °F

    Slight Chance
    Rain

  • Tonight

    Tonight: Mostly clear, with a low around 40. Northwest wind 8 to 11 mph, with gusts as high as 21 mph.

    Low: 40 °F

    Mostly Clear

  • Tuesday

    Tuesday: Partly sunny, then gradually becoming sunny, with a high near 59. Southwest wind 8 to 11 mph, with gusts as high as 22 mph.

    High: 59 °F

    Becoming
    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 45. West wind 7 to 9 mph, with gusts as high as 20 mph.

    Low: 45 °F

    Mostly Clear

  • Veterans Day

    Veterans Day: Sunny, with a high near 58. West wind 5 to 7 mph.

    High: 58 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 43.

    Low: 43 °F

    Mostly Cloudy

  • Thursday

    Thursday: A 50 percent chance of rain after 1pm. Mostly cloudy, with a high near 59.

    High: 59 °F

    Mostly Cloudy
    then Chance
    Rain

  • Thursday Night

    Thursday Night: Rain. Low around 40. Chance of precipitation is 80%.

    Low: 40 °F

    Rain

  • Friday

    Friday: Rain likely. Mostly cloudy, with a high near 48. Breezy. Chance of precipitation is 70%.

    High: 48 °F

    Rain Likely
    and Breezy

Detailed Forecast

This Afternoon
A 20 percent chance of rain before 4pm. Mostly sunny, with a high near 57. Northwest wind around 16 mph, with gusts as high as 31 mph.
Tonight
Mostly clear, with a low around 40. Northwest wind 8 to 11 mph, with gusts as high as 21 mph.
Tuesday
Partly sunny, then gradually becoming sunny, with a high near 59. Southwest wind 8 to 11 mph, with gusts as high as 22 mph.
Tuesday Night
Mostly clear, with a low around 45. West wind 7 to 9 mph, with gusts as high as 20 mph.
Veterans Day
Sunny, with a high near 58. West wind 5 to 7 mph.
Wednesday Night
Mostly cloudy, with a low around 43.
Thursday
A 50 percent chance of rain after 1pm. Mostly cloudy, with a high near 59.
Thursday Night
Rain. Low around 40. Chance of precipitation is 80%.
Friday
Rain likely. Mostly cloudy, with a high near 48. Breezy. Chance of precipitation is 70%.
Friday Night
A 30 percent chance of rain. Mostly cloudy, with a low around 35.
Saturday
Mostly cloudy, with a high near 48.
Saturday Night
Mostly cloudy, with a low around 35.
Sunday
Mostly sunny, with a high near 50.
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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:
1:27 pm EST Nov 9, 2026
Forecast Valid:
1pm EST Nov 9, 2026-6pm EST Nov 15, 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