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.

Fair

72°F

22°C

Humidity 87%
Wind Speed NW 7 mph
Barometer 29.94 in (1013.8 mb)
Dewpoint 68°F (20°C)
Visibility 10.00 mi
Last update 20 Aug 3:56 am EDT
Extended Forecast for

Islandia NY

Flood Watch August 20, 02:00pm until August 21, 02:00am
Click here for hazard details and duration
Flood Watch

  • Today

    Today: Showers and possibly a thunderstorm, mainly after 5pm. High near 84. Light and variable wind becoming south around 6 mph in the afternoon. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.

    High: 84 °F

    Sunny then
    Showers

  • Tonight

    Tonight: Showers and possibly a thunderstorm. Low around 65. Northeast wind 7 to 9 mph. Chance of precipitation is 80%. New precipitation amounts between 1 and 2 inches possible.

    Low: 65 °F

    Showers then
    Chance
    Showers

  • Friday

    Friday: A 20 percent chance of showers. Mostly cloudy, with a high near 79. Northeast wind 8 to 10 mph.

    High: 79 °F

    Slight Chance
    Showers

  • Friday Night

    Friday Night: Showers likely after 2am. Mostly cloudy, with a low around 67. Northeast wind around 5 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

    Low: 67 °F

    Mostly Cloudy
    then Showers
    Likely

  • Saturday

    Saturday: Showers. High near 77. East wind around 8 mph. Chance of precipitation is 80%. New precipitation amounts between three quarters and one inch possible.

    High: 77 °F

    Showers

  • Saturday Night

    Saturday Night: Showers. Low around 68. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

    Low: 68 °F

    Showers

  • Sunday

    Sunday: A 40 percent chance of showers. Partly sunny, with a high near 81.

    High: 81 °F

    Chance
    Showers

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 65.

    Low: 65 °F

    Partly Cloudy

  • Monday

    Monday: Sunny, with a high near 81.

    High: 81 °F

    Sunny

Detailed Forecast

Today
Showers and possibly a thunderstorm, mainly after 5pm. High near 84. Light and variable wind becoming south around 6 mph in the afternoon. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.
Tonight
Showers and possibly a thunderstorm. Low around 65. Northeast wind 7 to 9 mph. Chance of precipitation is 80%. New precipitation amounts between 1 and 2 inches possible.
Friday
A 20 percent chance of showers. Mostly cloudy, with a high near 79. Northeast wind 8 to 10 mph.
Friday Night
Showers likely after 2am. Mostly cloudy, with a low around 67. Northeast wind around 5 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.
Saturday
Showers. High near 77. East wind around 8 mph. Chance of precipitation is 80%. New precipitation amounts between three quarters and one inch possible.
Saturday Night
Showers. Low around 68. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.
Sunday
A 40 percent chance of showers. Partly sunny, with a high near 81.
Sunday Night
Partly cloudy, with a low around 65.
Monday
Sunny, with a high near 81.
Monday Night
Mostly clear, with a low around 62.
Tuesday
Sunny, with a high near 80.
Tuesday Night
Mostly clear, with a low around 63.
Wednesday
Mostly sunny, with a high near 81.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Islandia NY
 40.81°N 73.17°W (Elev. 161 ft)
Last Update:
2:27 am EDT Aug 20, 2026
Forecast Valid:
4am EDT Aug 20, 2026-6pm EDT Aug 26, 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