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

Watching Hurricane Erin; Heavy Rainfall Threat for Upper Midwest; Heatrisk for Mississippi Valley

Hurricane Erin continues to track westward with its outer bands bringing heavy rainfall and gusty winds for Puerto Rico and US Virgin Islands. Life-threatening surf and rip currents are occurring and will spread across the Atlantic coasts this week. Meanwhile, heavy rainfall and possible flooding are in the forecast for upper Midwest through Monday. Heatrisk continues for the Mississippi Valley. Read More >

Current conditions at

Galliano, South Lafourche Airport (KGAO)

Lat: 29.44°NLon: 90.26°WElev: 0ft.

Fair

76°F

24°C

Humidity 92%
Wind Speed Calm
Barometer 29.94 in
Dewpoint 73°F (23°C)
Visibility 10.00 mi
Heat Index76°F (24°C)
Last update 18 Aug 5:55 am CDT
Extended Forecast for

Grand Isle LA

  • Today

    Today: Mostly sunny, with a high near 90. Heat index values as high as 105. North wind around 5 mph becoming southeast in the afternoon.

    High: 90 °F

    Mostly Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 81. Southeast wind around 5 mph becoming calm.

    Low: 81 °F

    Partly Cloudy

  • Tuesday

    Tuesday: A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 89. Northeast wind around 5 mph.

    High: 89 °F

    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: A 30 percent chance of showers and thunderstorms, mainly after 4am. Mostly clear, with a low around 81. East wind around 5 mph becoming north after midnight.

    Low: 81 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: A 40 percent chance of showers and thunderstorms, mainly before 4pm. Sunny, with a high near 88. North wind around 5 mph becoming southeast in the afternoon.

    High: 88 °F

    Chance
    T-storms

  • Wednesday Night

    Wednesday Night: A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers and thunderstorms after 1am. Mostly clear, with a low around 81. Southeast wind around 5 mph becoming west after midnight. Chance of precipitation is 20%.

    Low: 81 °F

    Slight Chance
    T-storms

  • Thursday

    Thursday: A 40 percent chance of showers and thunderstorms. Sunny, with a high near 88. North wind around 5 mph becoming southeast in the afternoon.

    High: 88 °F

    Chance
    T-storms

  • Thursday Night

    Thursday Night: A 40 percent chance of showers and thunderstorms, mainly after 1am. Mostly clear, with a low around 80. South wind around 5 mph.

    Low: 80 °F

    Chance
    T-storms

  • Friday

    Friday: Showers and thunderstorms likely, mainly after 1pm. Mostly sunny, with a high near 87. Southwest wind around 5 mph.

    High: 87 °F

    T-storms
    Likely

Detailed Forecast

Today
Mostly sunny, with a high near 90. Heat index values as high as 105. North wind around 5 mph becoming southeast in the afternoon.
Tonight
Partly cloudy, with a low around 81. Southeast wind around 5 mph becoming calm.
Tuesday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 89. Northeast wind around 5 mph.
Tuesday Night
A 30 percent chance of showers and thunderstorms, mainly after 4am. Mostly clear, with a low around 81. East wind around 5 mph becoming north after midnight.
Wednesday
A 40 percent chance of showers and thunderstorms, mainly before 4pm. Sunny, with a high near 88. North wind around 5 mph becoming southeast in the afternoon.
Wednesday Night
A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers and thunderstorms after 1am. Mostly clear, with a low around 81. Southeast wind around 5 mph becoming west after midnight. Chance of precipitation is 20%.
Thursday
A 40 percent chance of showers and thunderstorms. Sunny, with a high near 88. North wind around 5 mph becoming southeast in the afternoon.
Thursday Night
A 40 percent chance of showers and thunderstorms, mainly after 1am. Mostly clear, with a low around 80. South wind around 5 mph.
Friday
Showers and thunderstorms likely, mainly after 1pm. Mostly sunny, with a high near 87. Southwest wind around 5 mph.
Friday Night
A chance of showers and thunderstorms. Partly cloudy, with a low around 79. Southwest wind around 5 mph.
Saturday
Showers and thunderstorms likely. Partly sunny, with a high near 87. West wind around 5 mph.
Saturday Night
A chance of showers and thunderstorms. Partly cloudy, with a low around 79. Southwest wind around 5 mph.
Sunday
Showers and thunderstorms likely. Mostly sunny, with a high near 86. West wind around 5 mph.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Grand Isle LA
 29.23°N 89.99°W
Last Update:
12:26 am CDT Aug 18, 2025
Forecast Valid:
6am CDT Aug 18, 2025-6pm CDT Aug 24, 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