The highest day temperature in September 2024 was 89°F. The lowest night temperature was 77°F. The average values for day and night temperatures during September were 85.7°F и 83.2°F respectivly.

The average sea surface temperature in September 2024 for Grand Isle was 88.2°F. The maximum and minimum values were 85.2°F and 90.6°F respectively.

Most of the days in September are sunny but you can also expect cloudy and gloomy days.

Precipitation total in September for Grand Isle is 2.6 in. It makes september one of the most rainy months of the year.

The average wind speed in September is 10.3 mph. It makes September one of the most windless months of the year for Grand Isle.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Grand Isle in September is 7.1 hours.