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

70°F

21°C

Humidity 84%
Wind Speed N 14 mph
Barometer 29.85 in (1010.6 mb)
Dewpoint 65°F (18°C)
Visibility 10.00 mi
Last update 23 Jun 1:56 pm EDT
Extended Forecast for

Mount Sinai NY

  • This Afternoon

    This Afternoon: Showers. Steady temperature around 67. Northwest wind around 8 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 67 °F

    Showers

  • Tonight

    Tonight: Showers likely, mainly before 8pm. Cloudy during the early evening, then gradual clearing, with a low around 64. Northwest wind 3 to 8 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

    Low: 64 °F

    Showers
    Likely then
    Partly Cloudy

  • Wednesday

    Wednesday: Sunny, with a high near 84. Northwest wind 7 to 9 mph.

    High: 84 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 65. West wind around 5 mph becoming calm after midnight.

    Low: 65 °F

    Partly Cloudy

  • Thursday

    Thursday: Sunny, with a high near 85. Calm wind becoming south around 6 mph in the afternoon.

    High: 85 °F

    Sunny

  • Thursday Night

    Thursday Night: Showers likely after 2am. Mostly cloudy, with a low around 67. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

    Low: 67 °F

    Partly Cloudy
    then Showers
    Likely

  • Friday

    Friday: Showers likely, mainly before 8am. Mostly cloudy, with a high near 84. Chance of precipitation is 60%.

    High: 84 °F

    Showers
    Likely

  • Friday Night

    Friday Night: Showers likely, mainly after 2am. Mostly cloudy, with a low around 68. Chance of precipitation is 60%.

    Low: 68 °F

    Showers
    Likely

  • Saturday

    Saturday: Showers likely, mainly before 2pm. Mostly cloudy, with a high near 80. Chance of precipitation is 60%.

    High: 80 °F

    Showers
    Likely

Detailed Forecast

This Afternoon
Showers. Steady temperature around 67. Northwest wind around 8 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.
Tonight
Showers likely, mainly before 8pm. Cloudy during the early evening, then gradual clearing, with a low around 64. Northwest wind 3 to 8 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Wednesday
Sunny, with a high near 84. Northwest wind 7 to 9 mph.
Wednesday Night
Partly cloudy, with a low around 65. West wind around 5 mph becoming calm after midnight.
Thursday
Sunny, with a high near 85. Calm wind becoming south around 6 mph in the afternoon.
Thursday Night
Showers likely after 2am. Mostly cloudy, with a low around 67. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Friday
Showers likely, mainly before 8am. Mostly cloudy, with a high near 84. Chance of precipitation is 60%.
Friday Night
Showers likely, mainly after 2am. Mostly cloudy, with a low around 68. Chance of precipitation is 60%.
Saturday
Showers likely, mainly before 2pm. Mostly cloudy, with a high near 80. Chance of precipitation is 60%.
Saturday Night
A 30 percent chance of showers before 8pm. Partly cloudy, with a low around 67.
Sunday
Sunny, with a high near 85.
Sunday Night
Partly cloudy, with a low around 68.
Monday
Mostly sunny, with a high near 86.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Mount Sinai NY
 40.95°N 73.02°W (Elev. 56 ft)
Last Update:
2:20 pm EDT Jun 23, 2026
Forecast Valid:
2pm EDT Jun 23, 2026-6pm EDT Jun 29, 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