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.

Partly Cloudy

26°C

78°F

Humidity 85%
Wind Speed S 9 km/h
Barometer 1017.6 mb (30.06 in)
Dewpoint 23°C (73°F)
Visibility 16 km
Heat Index27°C (80°F)
Last update 15 Jul 3:56 pm EDT
Extended Forecast for

Islip, Long Island Mac Arthur Airport NY

Heat Advisory July 16, 11:00am until July 17, 10:00pm
Click here for hazard details and duration
Heat Advisory

  • This Afternoon

    This Afternoon: A 20 percent chance of showers and thunderstorms before 5pm. Sunny, with a high near 30. South wind around 11 km/h.

    High: 30 °C

    Slight Chance
    T-storms

  • Tonight

    Tonight: Patchy fog after 3am. Otherwise, partly cloudy, with a low around 23. South wind 5 to 10 km/h becoming calm in the evening.

    Low: 23 °C

    Partly Cloudy
    then Patchy
    Fog

  • Wednesday

    Wednesday: Patchy fog before 8am. Otherwise, mostly sunny, with a high near 31. Heat index values as high as 35. Light southwest wind becoming south 11 to 16 km/h in the morning.

    High: 31 °C

    Patchy Fog
    then Mostly
    Sunny

  • Wednesday Night

    Wednesday Night: A 50 percent chance of showers and thunderstorms. Increasing clouds, with a low around 24. Southwest wind 13 to 16 km/h.

    Low: 24 °C

    Chance
    T-storms

  • Thursday

    Thursday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 2pm. Partly sunny, with a high near 31. Southwest wind 14 to 24 km/h. Chance of precipitation is 60%. New rainfall amounts between 1 and 2.5 mm, except higher amounts possible in thunderstorms.

    High: 31 °C

    Showers
    Likely

  • Thursday Night

    Thursday Night: Showers likely and possibly a thunderstorm before 8pm. Partly cloudy, with a low around 25. Chance of precipitation is 60%.

    Low: 25 °C

    Showers
    Likely then
    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 32.

    High: 32 °C

    Mostly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 21.

    Low: 21 °C

    Partly Cloudy

  • Saturday

    Saturday: Sunny, with a high near 29.

    High: 29 °C

    Sunny

Detailed Forecast

This Afternoon
A 20 percent chance of showers and thunderstorms before 5pm. Sunny, with a high near 30. South wind around 11 km/h.
Tonight
Patchy fog after 3am. Otherwise, partly cloudy, with a low around 23. South wind 5 to 10 km/h becoming calm in the evening.
Wednesday
Patchy fog before 8am. Otherwise, mostly sunny, with a high near 31. Heat index values as high as 35. Light southwest wind becoming south 11 to 16 km/h in the morning.
Wednesday Night
A 50 percent chance of showers and thunderstorms. Increasing clouds, with a low around 24. Southwest wind 13 to 16 km/h.
Thursday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 2pm. Partly sunny, with a high near 31. Southwest wind 14 to 24 km/h. Chance of precipitation is 60%. New rainfall amounts between 1 and 2.5 mm, except higher amounts possible in thunderstorms.
Thursday Night
Showers likely and possibly a thunderstorm before 8pm. Partly cloudy, with a low around 25. Chance of precipitation is 60%.
Friday
Mostly sunny, with a high near 32.
Friday Night
Partly cloudy, with a low around 21.
Saturday
Sunny, with a high near 29.
Saturday Night
Mostly cloudy, with a low around 22.
Sunday
A 40 percent chance of showers. Partly sunny, with a high near 29.
Sunday Night
A 30 percent chance of showers. Mostly cloudy, with a low around 22.
Monday
Mostly sunny, with a high near 30.
Monday Night
Partly cloudy, with a low around 22.
Tuesday
Mostly sunny, with a high near 28.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Islip, Long Island Mac Arthur Airport NY
 40.81°N 73.11°W (Elev. 98 m)
Last Update:
3:16 pm EDT Jul 15, 2025
Forecast Valid:
4pm EDT Jul 15, 2025-6pm EDT Jul 22, 2025
 
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