The highest day temperature in July 2025 was 95°F. The lowest night temperature was 85°F. The average values for day and night temperatures during July were 90.2°F и 87.0°F respectivly.

The average sea surface temperature in July 2025 for Grand Isle was 92.5°F. The maximum and minimum values were 90.2°F and 95.0°F respectively.

Most of the days in July are cloudy but you can also expect sunny or gloomy days.

Precipitation total in July for Grand Isle is 2.2 in. It makes july one of the most rainy months of the year.

The average wind speed in July is 8.9 mph. It makes July the most windless month 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 July is 7.4 hours.