Sargassum Tracker

All about sargassum: satellite images, forecasts and outlooks.

Forecast for November 7, 2025 - East winds 10 to 15 knots with gusts up to 20 knots. Waves 4-5 ft for the north coast and around 2-3 feet for the Caribbean side. Isolated showers. Rip currents. The St. John Buoy is out of service due to a sensor failure. .

USF OOL Long Term Outlook

LAST UPDATE: Oct 31, 2025

As predicted last month, the total amount of Sargassum in each of the five regions continued to decline in October. Similar to what happened in September, the decline in October was substantial in all but the East Atlantic region, with total Sargassum amount more than halved again. Most Sargassum is now in the East Atlantic, followed by the eastern Caribbean region. In the Gulf of America, Sargassum amount is now negligible (<0.02 metric tons). Despite such sharp declines, total Sargassum amount in the eastern Caribbean and West Atlantic still shows the highest in history for the month of October, but most of this biomass is around Dominica Republic and Haiti. Overall, the inundation pressure should have decreased substantially for all regions in October.

Looking ahead: Total Sargassum amount in all regions is likely to continue to decline, possibly reaching the annual minimum in November. Correspondingly, most regions should be free of massive inundations, as the Sargassum “season” is over. One possible exception is the East Atlantic, where the total Sargassum amount will likely remain relatively high even after further declines in November. Meanwhile, we will keep a close eye on the temporal changes of Sargassum amount in all regions. More info: Sargassum Watch System (SaWS).

SARGASSUM ABUNDANCE INTENSITY

Details

Since 2011, large amounts of Sargassum seaweed have appeared in the Caribbean Sea every summer except 2013, creating many environmental, ecological, and economic problems in many regions. The seaweed originated from the tropical Atlantic and is believed to be a result of climate variability and other natural and unnatural processes. Based on satellite observations and statistics of historical events, in early February 2018, the Optical Oceanography Lab developed the first 1-page Sargassum outlook bulletin for the Caribbean Sea. Since then, the bulletins have been generated and distributed to subscribers by the last day of the month. These monthly bulletins are also made available at the bottom of the SaWS page.

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Disclaimer

The information bulletin is meant to provide a general outlook of current bloom condition and future bloom probability for the Caribbean Sea. By no means should it be used for commercial purpose, or used for predicting bloom conditions for a specific location or beach. The authors of this bulletin, as well as Caricoos, USF and NASA, take no responsibility for improper use or interpretation of the bulletin. Any use of the image, data, or graph from this bulletin page in reports or publications should obtain permission from the USF OOL group.