Data
Caribbean sargassum season by island
How strong sargassum gets around 21 Caribbean destinations, month by month, from satellite data since January 2018.
Updated 4 Nov 2026 · Data through October 2026 · License: CC BY 4.0
All islands in June
| Island | Signal this month | Peak month | Signal at its peak | Quietest month |
|---|---|---|---|---|
| Bahamas (Exuma) | 0.2% | November | 0.6% | June |
| Bahamas (Harbour Island) | 0.3% | January | 0.9% | May |
| Bahamas (Nassau) | 0.3% | January | 1.6% | April |
| Curacao | 0.4% | January | 3.1% | July |
| Aruba | 0.5% | January | 2.6% | July |
| Turks and Caicos (Providenciales) | 0.7% | August | 4.1% | May |
| Grenada | 2.7% | May | 7.5% | November |
| Grand Cayman | 4.0% | July | 7.4% | November |
| Virgin Gorda | 5.0% | July | 5.6% | November |
| Mustique | 5.8% | May | 8.9% | November |
| Dorado | 5.9% | June | 5.9% | December |
| St. John | 6.0% | June | 6.0% | November |
| Barbados | 7.0% | May | 13.5% | November |
| Anguilla | 7.4% | July | 8.3% | October |
| St. Barts | 7.4% | July | 8.3% | November |
| St. Martin | 8.2% | July | 8.3% | October |
| St. Lucia | 9.7% | May | 13.6% | November |
| Jamaica (Montego Bay) | 11.0% | June | 11.0% | February |
| Antigua | 11.4% | June | 11.4% | November |
| Tulum | 18.2% | July | 19.5% | January |
| Punta Cana | 29.1% | June | 29.1% | February |
The signal is the share of clear sea within about 35 miles of the island that reads as floating algae.
St. Barts through the year
Signal month by month
Peak: 8.3%
Highest in July, at 8.3%.
May to August, year by year
Peak: 14.1%
East Caribbean, May to August, year by year
Peak: 10.2%
2026 is the highest year in this series at 10.2%, ahead of 2025 at 9.9%. It averages ten destinations from Puerto Rico to Grenada.
West Caribbean, May to August, year by year
Peak: 17.4%
It averages Jamaica, Grand Cayman and Tulum.
Use these numbers
Quote it
In June, the sargassum signal around Punta Cana reaches 29.1%, against 0.2% around Exuma, according to Gladori’s reading of NOAA satellite data since 2018.
Full citation:
Gladori, Caribbean sargassum season by island (2026), https://gladori.com/data/caribbean-sargassum-season/. Updated 4 Nov 2026. Sargassum data: USF AFAI via NOAA AOML.
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Free to reuse under CC BY 4.0. Each file carries its sources in the first lines.
Questions about sargassum season
When is sargassum season in the Caribbean?
In our satellite series, the signal peaks between May and July at most of the 21 destinations and fades by October. Turks and Caicos peaks later, in August. The Bahamas, Aruba and Curacao stay low all year.
Which islands get the least sargassum?
In June, Exuma had the lowest signal of the 21 destinations (0.2%) and Punta Cana the highest (29.1%). The table above changes with the month.
Was 2026 a bad year for sargassum?
In the east Caribbean it was the highest May to August in this series, at 10.2%, ahead of 2025 at 9.9%. The chart by year has the rest.
Does this tell me what my beach will look like?
No. The signal compares islands and months over open water, and it says nothing about one beach on one day. For the current week, see sargassum this week.
Method and limits
- The data is the University of South Florida floating algae index (7-day AFAI fields), served by NOAA AOML and sampled about once a week since January 2018.
- The signal is the share of clear sea pixels in a box about 70 miles (110 km) wide with an index above zero. Monthly figures average every year on record for that month.
- Reefs and shallow water read above zero all year, so any pixel above zero in more than a quarter of its samples is dropped. A stricter cutoff lowers every figure and can move an island a few places. The broad groups hold.
- Clouds hide pixels and satellites miss the water right at the shore.
- The signal compares islands and months. It is not tonnage.
- The sargassum data is not intended for legal use, so these figures do not support a claim or an insurance case.
Sources
| Source | What it gives | Terms |
|---|---|---|
| USF AFAI via NOAA AOML | 7-day floating algae index since June 2016 | May be used and redistributed for free. Not intended for legal use. No warranty from the contributor, NOAA or the US government. |