Blue Dolphin Inn & Cottages — Information on this website contains the actual local weather in Grand Isle, LA and the monthly average temperature.
Currently
Weather — Grand Isle’s Monthly Average Temperature
| Month | Temp. (min) | Temp. (max) | Temp. (avg) |
| January | 38°F | 74°F | 58°F |
| February | 35°F | 73°F | 60°F |
| March | 39°F | 79°F | 66°F |
| April | 45°F | 84°F | 71°F |
| May | 63°F | 89°F | 77°F |
| June | 72°F | 91°F | 83°F |
| July | 72°F | 92°F | 84°F |
| August | 71°F | 92°F | 84°F |
| September | 71°F | 89°F | 82°F |
| October | 51°F | 87°F | 73°F |
| November | 44°F | 78°F | 64°F |
| December | 33°F | 74°F | 59°F |
