Grand Isle Beach sargassum & beach forecast
Grand Isle, LA · Louisiana Coast, United States · 29.236, -89.987
Updated : very low seaweed, beach grade B, sea 71°F.
Veabird's call
Wednesday grades B+ with very low seaweed, quiet crowds and 6% rain.
Best months are August (A-) and October (A-), plus fishing charters when rip risk is High.
Grades from Veabird's beach forecast; wording by AI (Muse Spark), checked against the forecast. Updated Nov 15, 18:00 UTC.
Tell me when Grand Isle Beach is clear
One email when the seaweed clears or the beach grades A, at most once a week per beach. We only ask for your email address, and every email has a one-click unsubscribe.
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Questions about Grand Isle Beach
Does Grand Isle Beach get sargassum (seaweed)?
Only a little in most years. At Grand Isle Beach the typical-year risk stays low, even around July, the usual peak (moderate or heavier seaweed on the beach in an estimated 12% of weeks). Landings vary by year, wind and currents.
How warm is the water at Grand Isle Beach?
About 73°F in November. The sea is warmest in August (about 89°F) and coolest in January (about 61°F).
When is the best time to visit Grand Isle Beach?
For warm water and dry weather, aim for October. October brings about 7 rainy days and a sea near 79°F.
When is hurricane season at Grand Isle Beach, and how often do storms hit?
The Atlantic hurricane season runs June through November and peaks around September. A tropical storm passed within 86 miles of Grand Isle Beach in 21 of the 55 seasons from 1971 to 2025, and a hurricane within 58 miles in 10. The riskiest stretch is around September 3, when the chance of a storm passing in any one week is about 5%; across all of September it is about 15%. Flexible bookings and travel insurance help in the peak weeks.
Sargassum season at Grand Isle Beach Rentals
Low sargassum risk year-round at Grand Isle Beach Rentals: even around July, the usual peak, Veabird estimates moderate or heavier seaweed on the beach in about 12% of weeks. Actual landings vary a lot by year, wind and currents; check the live conditions above.
Estimated share of weeks in each month with moderate or heavier seaweed on the beach. Veabird takes the landing season seen on Quintana Roo's beaches (a Puerto Morelos beach camera, 2015–2020, and the Mexican Navy's beach alerts, 2022–2026), the nearest coast with a multi-year beach record (this one has none), and scales it by how often NOAA AOML satellites see notable seaweed within about 20 km of this stretch of coast: 10% of weeks here on average, against 54% off Quintana Roo, so 18% of that season. The satellite share (2016–2024, the top fifth of all coast-weeks, adjusted for this beach's exposure of 40%) measures seaweed offshore, not on the sand: off the Riviera Maya it reads high even in winter, when little lands. Very low under 10%, Low 10–24%, Moderate 25–44%, High 45–69%, Very high 70%+. Beach faces 150°; onshore winds from that direction push seaweed ashore. Satellite sargassum data: USF Optical Oceanography Lab (Sargassum Watch System) via NOAA AOML. The satellite record as open data.
The Louisiana coast month by month
Typical weather, water temperature, seaweed and crowds for every month: the best time to visit the Louisiana coast.
- The Louisiana coast in January
- The Louisiana coast in February
- The Louisiana coast in March
- The Louisiana coast in April
- The Louisiana coast in May
- The Louisiana coast in June
- The Louisiana coast in July
- The Louisiana coast in August
- The Louisiana coast in September
- The Louisiana coast in October
- The Louisiana coast in November
- The Louisiana coast in December
Weather, water & seaweed by month at Grand Isle Beach Rentals
Average highs run from about 62°F in January to 87°F in August. The sea is warmest in August (about 89°F) and coolest in January (about 61°F). February, October and November are usually the driest, with about 7 rainy days each; July is the wettest, with about 20 rainy days.
| Month | Avg high | Sea | Rainy days | Sargassum |
|---|---|---|---|---|
| Jan | 62°F | 61°F | 10 | Very low |
| Feb | 64°F | 62°F | 7 | Very low |
| Mar | 69°F | 68°F | 9 | Very low |
| Apr | 73°F | 74°F | 8 | Very low |
| May | 79°F | 80°F | 13 | Very low |
| Jun | 84°F | 85°F | 14 | Low |
| Jul | 86°F | 88°F | 20 | Low |
| Aug | 87°F | 89°F | 17 | Very low |
| Sep | 84°F | 85°F | 14 | Very low |
| Oct | 77°F | 79°F | 7 | Very low |
| Nov | 71°F | 73°F | 7 | Very low |
| Dec | 66°F | 65°F | 8 | Very low |
Monthly averages from 6 years of ERA5 reanalysis (Open-Meteo) for this area's 0.5° grid cell; rainy days have at least 1 mm (0.04 in). Sargassum is the typical-year estimate described above. Any given year can differ.
Cleanup & barriers
- Offshore barriers
- None.
- Public cleanup
- Limited: Grand Isle town crews after large events.
- Resort crews
- Minimal; rentals rely on town crews.
- Typical clearing time
- 2–5 days
Safety notes
US domestic
- Swim advisories for bacteria after rain (LDH).
- Very remote; limited lifeguards.
Check official advisories and local flags before swimming. Decomposing sargassum releases hydrogen sulfide; avoid heavy piles.
Things to do near Grand Isle, LA
- Grand Isle State Park
- Fishing charters
- New Orleans French Quarter (2 hr)
Fly in for the best beach days
Suggested dates are a week in October. Change them to match the live forecast above.
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Nearest airports
- New Orleans Louis Armstrong Intl (MSY), ~88 km
Nearby resorts
- Bay St. Louis Beach Hotels Bay St. Louis, MS · 135 km
- The Inn at Long Beach Gulfport, MS · 147 km
- Island View Casino Resort Gulfport, MS · 151 km
- Courtyard by Marriott Gulfport Beachfront Gulfport, MS · 153 km
- Quality Inn Biloxi Beach Biloxi, MS · 161 km
- Days Inn by Wyndham Biloxi Beach Biloxi, MS · 163 km
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