National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hazardous Weather Conditions

Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

Mostly Cloudy

51°F

11°C

Humidity 45%
Wind Speed NW 14 G 23 mph
Barometer 30.12 in (1020.0 mb)
Dewpoint 30°F (-1°C)
Visibility 10.00 mi
Wind Chill46°F (8°C)
Last update 20 Apr 12:56 pm EDT
Extended Forecast for

Stony Brook NY

Freeze Warning April 21, 12:00am until April 21, 09:00am
Click here for hazard details and duration
Freeze Warning

  • This Afternoon

    This Afternoon: A 20 percent chance of showers. Partly sunny, with a high near 51. Northwest wind 14 to 16 mph.

    High: 51 °F

    Slight Chance
    Showers

  • Tonight

    Tonight: Partly cloudy, with a low around 32. Wind chill values between 25 and 30. North wind around 9 mph.

    Low: 32 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Sunny, with a high near 53. North wind around 6 mph becoming southwest in the afternoon.

    High: 53 °F

    Sunny

  • Tuesday Night

    Tuesday Night: A 30 percent chance of showers after 2am. Increasing clouds, with a low around 39. South wind around 8 mph.

    Low: 39 °F

    Mostly Cloudy
    then Chance
    Showers

  • Wednesday

    Wednesday: A 30 percent chance of showers, mainly before 8am. Mostly cloudy, with a high near 58. South wind around 9 mph.

    High: 58 °F

    Chance
    Showers

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 45.

    Low: 45 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 64.

    High: 64 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 46.

    Low: 46 °F

    Mostly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 62.

    High: 62 °F

    Mostly Sunny

Detailed Forecast

This Afternoon
A 20 percent chance of showers. Partly sunny, with a high near 51. Northwest wind 14 to 16 mph.
Tonight
Partly cloudy, with a low around 32. Wind chill values between 25 and 30. North wind around 9 mph.
Tuesday
Sunny, with a high near 53. North wind around 6 mph becoming southwest in the afternoon.
Tuesday Night
A 30 percent chance of showers after 2am. Increasing clouds, with a low around 39. South wind around 8 mph.
Wednesday
A 30 percent chance of showers, mainly before 8am. Mostly cloudy, with a high near 58. South wind around 9 mph.
Wednesday Night
Mostly cloudy, with a low around 45.
Thursday
Mostly sunny, with a high near 64.
Thursday Night
Mostly cloudy, with a low around 46.
Friday
Mostly sunny, with a high near 62.
Friday Night
Partly cloudy, with a low around 44.
Saturday
A 30 percent chance of showers. Partly sunny, with a high near 57.
Saturday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 43.
Sunday
A 30 percent chance of showers. Mostly cloudy, with a high near 58.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Stony Brook NY
 40.9°N 73.12°W (Elev. 148 ft)
Last Update:
9:27 am EDT Apr 20, 2026
Forecast Valid:
2pm EDT Apr 20, 2026-6pm EDT Apr 26, 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