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

61°F

16°C

Humidity 90%
Wind Speed NE 6 mph
Barometer 30.14 in (1020.4 mb)
Dewpoint 58°F (14°C)
Visibility 10.00 mi
Last update 16 Jun 3:56 am EDT
Extended Forecast for

Stony Brook NY

  • Overnight

    Overnight: A 20 percent chance of light rain. Mostly cloudy, with a low around 60. East wind around 6 mph.

    Low: 60 °F

    Slight Chance
    Light Rain

  • Monday

    Monday: Mostly cloudy, with a high near 69. East wind around 8 mph.

    High: 69 °F

    Mostly Cloudy

  • Monday Night

    Monday Night: A 20 percent chance of light rain after 2am. Mostly cloudy, with a low around 61. East wind around 6 mph.

    Low: 61 °F

    Mostly Cloudy
    then Slight
    Chance Light
    Rain

  • Tuesday

    Tuesday: A slight chance of light rain before 8am, then a slight chance of showers after 2pm. Mostly cloudy, with a high near 73. East wind 6 to 8 mph. Chance of precipitation is 20%.

    High: 73 °F

    Cloudy then
    Slight Chance
    Showers

  • Tuesday Night

    Tuesday Night: A 50 percent chance of showers, mainly after 8pm. Cloudy, with a low around 63. South wind 3 to 6 mph.

    Low: 63 °F

    Chance
    Showers

  • Wednesday

    Wednesday: A 30 percent chance of showers before 2pm. Cloudy, then gradually becoming mostly sunny, with a high near 82.

    High: 82 °F

    Chance
    Showers

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 68.

    Low: 68 °F

    Partly Cloudy

  • Juneteenth

    Juneteenth: A 30 percent chance of showers and thunderstorms after 2pm. Sunny, with a high near 90.

    High: 90 °F

    Sunny then
    Chance
    T-storms

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 2am. Partly cloudy, with a low around 68. Chance of precipitation is 30%.

    Low: 68 °F

    Chance
    T-storms then
    Chance
    Showers

Detailed Forecast

Overnight
A 20 percent chance of light rain. Mostly cloudy, with a low around 60. East wind around 6 mph.
Monday
Mostly cloudy, with a high near 69. East wind around 8 mph.
Monday Night
A 20 percent chance of light rain after 2am. Mostly cloudy, with a low around 61. East wind around 6 mph.
Tuesday
A slight chance of light rain before 8am, then a slight chance of showers after 2pm. Mostly cloudy, with a high near 73. East wind 6 to 8 mph. Chance of precipitation is 20%.
Tuesday Night
A 50 percent chance of showers, mainly after 8pm. Cloudy, with a low around 63. South wind 3 to 6 mph.
Wednesday
A 30 percent chance of showers before 2pm. Cloudy, then gradually becoming mostly sunny, with a high near 82.
Wednesday Night
Partly cloudy, with a low around 68.
Juneteenth
A 30 percent chance of showers and thunderstorms after 2pm. Sunny, with a high near 90.
Thursday Night
A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 2am. Partly cloudy, with a low around 68. Chance of precipitation is 30%.
Friday
Sunny, with a high near 84.
Friday Night
Partly cloudy, with a low around 63.
Saturday
Sunny, with a high near 82.
Saturday Night
Partly cloudy, with a low around 66.
Sunday
Mostly sunny, with a high near 86.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.92°N 73.12°W (Elev. 112 ft)
Last Update:
6:40 pm EDT Jun 15, 2025
Forecast Valid:
4am EDT Jun 16, 2025-6pm EDT Jun 22, 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