Rising levels of Sargassum seaweed across the Atlantic are pointing toward another major bloom year in 2026, even as early long-range forecasts suggest the upcoming Atlantic hurricane season may fall close to historical averages.
According to the University of South Florida Optical Oceanography Lab’s Sargassum Watch System (SaWS), Sargassum amounts reached record-high levels in February 2026. The latest SaWS monthly bulletin, released February 28, reported continued growth across the Western Caribbean, Western Atlantic, and Eastern Atlantic.
The forecast indicates that 2026 is expected to be a “major Sargassum year,” meaning total abundance is projected to exceed 75% of historical values. Beaching events are already occurring in parts of the region and are expected to increase along the windward sides of the Lesser Antilles and the Western Caribbean in the coming months. By contrast, levels in the Gulf of Mexico are projected to remain relatively low.
Additional monitoring tools support the outlook. NOAA CoastWatch and the collaborative Sargassum Inundation Risk product developed with the University of South Florida confirm that above-normal levels persisted through late February 2026, with continued growth expected in the near term.
The trend marks the continuation of a region-wide Sargassum issue that began in 2011, when large blooms of the floating seaweed began appearing across the Atlantic basin and affecting Caribbean coastlines.
While Sargassum levels are already trending upward, early hurricane forecasts indicate that the 2026 Atlantic hurricane season may be close to the long-term average.
The most recent extended-range projection comes from Tropical Storm Risk (TSR), which released its seasonal outlook on December 11, 2025 using data through November 2025. According to TSR, the upcoming season is expected to produce 14 named storms, 7 hurricanes, and 3 major hurricanes — defined as Category 3 or stronger.
TSR also projects an Accumulated Cyclone Energy (ACE) index of approximately 125. That figure is very close to the 30-year average from 1991 to 2020, which stands at 122 ACE, 14.4 named storms, and 7.2 hurricanes.
The forecast cites anticipated warm-neutral ENSO conditions and above-average sea surface temperatures in the Atlantic’s main development region as factors supporting near-normal activity. However, the outlook also notes considerable uncertainty, particularly because the potential development of El Niño conditions later in 2026 could alter storm activity.
Probability analysis from TSR shows a 49% likelihood of activity falling within the middle tercile of historical ranges, a 32% chance of above-normal activity, and a 19% chance of below-normal activity.
No other official seasonal forecasts have yet been released. Both the National Oceanic and Atmospheric Administration and Colorado State University typically publish their official hurricane outlooks later in the spring. NOAA’s forecast is generally issued in mid-May.
The official Atlantic hurricane season runs from June 1 through November 30.
Advertisements
