Grand Isle in september: average Weather, Temperature and Climate
Weather in Grand Isle in september 2025
The weather in Grand Isle in september comes from statistical datas on the past years. You can view the weather statistics the entire month, but also navigating through the tabs for the beginning, the middle and the end of the month.
Average weather throughout september
good weather UV index: 7
Weather at 6am
81°F
Clear/Sunny
41% of time
26%
24%
8%
Weather at 12pm
85°F
Clear/Sunny
46% of time
26%
18%
8%
Weather at 6pm
83°F
Clear/Sunny
57% of time
19%
17%
7%
Weather at 3am
81°F
43%
25%
22%
8%
Evolution of daily average temperature and precipitation in Grand Isle in september
These charts show the evolution of average minimum/maximum temperatures as well as average daily precipitation volume in Grand Isle in september.
The climate of Grand Isle in september is good
The climate in september in Grand Isle is wet (with 7in of rainfall over 11 days). The weather is better from the previous month since in august it receives an average of 11.3in of precipitation over 16 days.
The climate enjoyable in that locality september. The high seasonal norm is 86°F. The minimum is 81°F. Thus, the mean temperature average on this month of september in Grand Isle is 83°F. These temperatures are far removed from those records observed in Grand Isle in the month of september with a maximum record of 94°F in 2019 and a minimum record of 67°F in 2011. You You can hope to have about 14 days with temperatures up to 86°F, or 47 of the month.
On this month of september, day length in Grand Isle is generally 12:20. The sun rises at 06:45 and sunset is at 19:05.
With good weather conditions, september is recommended to go in this locality in Louisiana.
Seasonal average climate and temperature of Grand Isle in september
Check below seasonal norms These statistics are generated from the weather statements of the last years of september.
| September | |||||
| Outside temperature | |||||
| Average temperature | 83°F | ||||
| Highest temperature | 86°F | ||||
| Lowest temperature | 81°F | ||||
| Highest record temperature | 94°F (2019) | ||||
| Lowest record temperature | 67°F (2011) | ||||
| Number of days at +86°F | 14 day(s) (47%) | ||||
| Number of days at +65°F | 30 day(s) (100%) | ||||
| Sea temperature | |||||
| Average sea temperature | 84°F | ||||
| Lowest sea temperature | 80°F | ||||
| Highest sea temperature | 88°F | ||||
| Wind | |||||
| Wind speed | 20km/h | ||||
| Wind temperature | 81°F | ||||
| Precipitation (rainfall) | |||||
| Rainfall | 7in | ||||
| Number of days with rainfall | 11 day(s) (35%) | ||||
| Record daily rainfall | 4.5in (2011) | ||||
| Other climate data | |||||
| Humidity | 79% | ||||
| Visibility | 9.49km | ||||
| Cloud cover | 26% | ||||
| UV index | 7 | ||||
| Daily sunshine hours | 11 | ||||
| Sunrise and sunset | |||||
| Time of sunrise | 06:45 | ||||
| Time of sunset | 19:05 | ||||
| Length of day | 12:20 | ||||
| Our opinion about the weather in september | |||||
| Our opinion at whereandwhen.net | good | ||||
How was the weather last september?
Here is the day by day recorded weather in Grand Isle in september 2024:
81°F to 83°F
81°F to 86°F
83°F to 85°F
83°F to 83°F
79°F to 83°F
77°F to 83°F
74°F to 79°F
77°F to 81°F
77°F to 85°F
79°F to 83°F
79°F to 83°F
77°F to 81°F
74°F to 83°F
79°F to 85°F
79°F to 85°F
79°F to 85°F
79°F to 81°F
77°F to 79°F
79°F to 81°F
79°F to 81°F
77°F to 83°F
81°F to 83°F
79°F to 83°F
79°F to 83°F
77°F to 83°F
77°F to 83°F
72°F to 79°F
79°F to 85°F
81°F to 85°F
81°F to 83°F
Map: other cities in Louisiana in september
Cities near Grand Isle:
| Port Sulphur in september | good weather |
| New Orleans in september | good weather |
| Houma in september | good weather |
| Slidell in september | good weather |
| Morgan City in september | good weather |
| Baton Rouge in september | good weather |
| Marsh Island in september | good weather |
| New Iberia in september | good weather |
| Pecan Island in september | good weather |
| Opelousas in september | good weather |
| Marksville in september | good weather |
| Oakdale in september | good weather |
Click over cities on the map for information about the weather in september.
Grand Isle
perfect weather
good
tolerable
bad
very bad
Weather data for Grand Isle in september:
Weather data for Grand Isle for september are derived from an average of the weather forecast since 2009 in Grand Isle. There is a margin of error and these forecasts are to be considered as general information only. The weather in Grand Isle can vary slightly from year to year, but this data should limit surprises. So you can pack your bags or check for the best time in year to go to Grand Isle.