This data the coastal Grand Isle water temperature today, tomorrow and the upcoming days. Besides, you can also get information about the weather and surf forecast, as well as the data on sunrise / sunset and moonrise / moonset at a given point on any given day.
Water temperature in Grand Isle today is 70.5°F. Based on our historical data over a period of ten years, the warmest water in this day in Grand Isle was recorded in 2015 and was 73.9°F, and the coldest was recorded in 2017 at 67.1°F. Water temperature in Grand Isle is expected to drop to 68.9°F in the next 10 days. September average water temperature in Grand Isle is 68.7°F, the minimum temperature is 61.5°F, and the maximum is 75.7°F.
The swimming season in Grand Isle lasts from July to September. During those months, Grand Isle water temperature does not drop below 68°F and therefore suitable for comfortable swimming. The average water temperature in Grand Isle in winter reaches 37.9°F, in spring 41°F, in summer the average temperature rises to 69.8°F, and in autumn it is 59.7°F.
September 5, 2025 |
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today temp |
70.5°F |
September 4, 2025 |
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yesterday temp |
71.6°F |
Data in a table show Grand Isle temperature today (September 5, 2025). For more information and forecast for a few days, go to the weather forecast Grand Isle.
0-3 h | 3-6 h | 6-9 h | 9-12 h |
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62.6°F | 59.2°F | 55.4°F | 60.1°F |
12-15 h | 15-18 h | 18-21 h | 21-24 h |
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72.3°F | 75.9°F | 75.7°F | 72.3°F |
You may also be interested in other sections of our site for Grand Isle: Sunrise and Sunset
These figures shows the average, minimum and maximum monthly water temperature in Grand Isle. In addition to the table values, the graph below displays of changes average surface temperature during the year. Values are calculated based on the data over the past 10 years. Using them, you can check the water temperature in Grand Isle on any day of this period that interests you. Click on the month link and you will see a table for each day, or alternatively you can view the temperature curve of the month and select 2 different years you want to compare, either in a table or as a curve
Month | Avr | Min | Max | |
---|---|---|---|---|
January | 37.4°F | 33.6°F | 42.3°F | cold |
Water temperature in Grand Isle in January | ||||
February | 33.8°F | 31.1°F | 37.6°F | cold |
Water temperature in Grand Isle in February | ||||
March | 33.3°F | 30.9°F | 39.4°F | cold |
Water temperature in Grand Isle in March | ||||
April | 38.8°F | 32.5°F | 46.4°F | cold |
Water temperature in Grand Isle in April | ||||
May | 51.1°F | 40.6°F | 62.8°F | cold |
Water temperature in Grand Isle in May | ||||
June | 63.1°F | 53.6°F | 77.2°F | cold |
Water temperature in Grand Isle in June | ||||
July | 72.7°F | 64.8°F | 77.7°F | warm |
Water temperature in Grand Isle in July | ||||
August | 73.8°F | 69.6°F | 78.8°F | warm |
Water temperature in Grand Isle in August | ||||
September | 68.7°F | 61.5°F | 75.7°F | warm |
Water temperature in Grand Isle in September | ||||
October | 59.7°F | 52.5°F | 67.6°F | cold |
Water temperature in Grand Isle in October | ||||
November | 50.9°F | 44.1°F | 57.7°F | cold |
Water temperature in Grand Isle in November | ||||
December | 42.8°F | 37.2°F | 48.6°F | cold |
Water temperature in Grand Isle in December |