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

40°F

4°C

Humidity 100%
Wind Speed W 5 mph
Barometer 29.74 in (1007.0 mb)
Dewpoint 40°F (4°C)
Visibility 7.00 mi
Wind Chill36°F (2°C)
Last update 21 Mar 3:56 am EDT
Extended Forecast for

Islip NY

  • Today

    Today: Mostly cloudy, then gradually becoming sunny, with a high near 54. North wind 6 to 9 mph.

    High: 54 °F

    Decreasing
    Clouds

  • Tonight

    Tonight: Increasing clouds, with a low around 39. Light and variable wind.

    Low: 39 °F

    Increasing
    Clouds

  • Sunday

    Sunday: A 30 percent chance of rain after 2pm. Mostly cloudy, with a high near 54. Southwest wind 7 to 10 mph.

    High: 54 °F

    Mostly Cloudy
    then Chance
    Rain

  • Sunday Night

    Sunday Night: Rain and thunderstorms likely, then rain after 11pm. Low around 38. Southwest wind around 6 mph becoming north after midnight. Chance of precipitation is 80%. New precipitation amounts between a half and three quarters of an inch possible.

    Low: 38 °F

    Rain

  • Monday

    Monday: Rain, mainly before 8am. High near 47. North wind 9 to 11 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 47 °F

    Rain then
    Chance Rain

  • Monday Night

    Monday Night: Mostly clear, with a low around 30.

    Low: 30 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 45.

    High: 45 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 34.

    Low: 34 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Partly sunny, with a high near 49.

    High: 49 °F

    Partly Sunny

Detailed Forecast

Today
Mostly cloudy, then gradually becoming sunny, with a high near 54. North wind 6 to 9 mph.
Tonight
Increasing clouds, with a low around 39. Light and variable wind.
Sunday
A 30 percent chance of rain after 2pm. Mostly cloudy, with a high near 54. Southwest wind 7 to 10 mph.
Sunday Night
Rain and thunderstorms likely, then rain after 11pm. Low around 38. Southwest wind around 6 mph becoming north after midnight. Chance of precipitation is 80%. New precipitation amounts between a half and three quarters of an inch possible.
Monday
Rain, mainly before 8am. High near 47. North wind 9 to 11 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.
Monday Night
Mostly clear, with a low around 30.
Tuesday
Sunny, with a high near 45.
Tuesday Night
Mostly cloudy, with a low around 34.
Wednesday
Partly sunny, with a high near 49.
Wednesday Night
Mostly cloudy, with a low around 35.
Thursday
Mostly cloudy, with a high near 49.
Thursday Night
Rain likely. Mostly cloudy, with a low around 39. Chance of precipitation is 60%.
Friday
Rain likely. Partly sunny, with a high near 50. Chance of precipitation is 60%.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Islip NY
 40.73°N 73.22°W (Elev. 7 ft)
Last Update:
2:34 am EDT Mar 21, 2026
Forecast Valid:
4am EDT Mar 21, 2026-6pm EDT Mar 27, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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