The latest Caribbean Coral Reef Watch bulletin (Volume XI, Issue IV, covering August to November 2026) reports Bleaching Alert Level 1 and 2 heat stress across Florida, The Bahamas and Cuba as of 11 August 2026, with significant heat stress expected to spread south through the basin over the coming months. The bulletin is produced by the Caribbean Institute for Meteorology and Hydrology (CIMH) in partnership with NOAA Coral Reef Watch, and draws on NOAA CRW’s 5 km satellite products and Regional Virtual Stations.
Current conditions across the wider Caribbean
As of 11 August, The Bahamas, Florida and Cuba were experiencing Alert Level 1 and 2 heat stress, alongside limited stretches of the western and southern Caribbean coastlines. Most other Caribbean waters sat under Bleaching Watch conditions, with parts of the northern Caribbean and northwestern Atlantic under Bleaching Warning. Alert Level 1 carries a risk of reef wide bleaching. Alert Level 2 carries a risk of reef wide bleaching with mortality of heat sensitive corals.
Across NOAA CRW’s Regional Virtual Stations, 24% of Caribbean stations were registering Alert Level 1 to 5 heat stress, including stations in The Bahamas, Florida, Veracruz and the Yucatan Peninsula.
A global picture of thermal stress
The bulletin records Alert Level 1 to 5 heat stress at approximately 86% of Eastern Pacific stations, 70% of East Asia stations and 36% of Micronesia stations, as well as the Line Islands, the Ogasawara Islands, the Malacca Strait, Sabah in Malaysia, and the Gulf of Oman. High instantaneous heat stress, defined as HotSpot values of 1°C or higher, is most active across the central and eastern equatorial Pacific, the eastern and northwestern North Pacific, and parts of the northern Atlantic.
Outlook to November 2026
NOAA CRW’s four month probabilistic outlook of 11 August gives a greater than 70% probability that most of the Caribbean basin will experience Alert Level 1 heat stress, arriving sequentially from north to south by the end of October and early November, following the seasonal cycle.
At the 60% probability threshold, the outlook predicts:
- Alert Level 1 and 2 conditions continuing across northern and central reefs of The Bahamas through August
- Spread to the entire Bahamas and most of Cuba in September
- Alert Level 1 conditions reaching Turks and Caicos, the Cayman Islands, Jamaica, the Leeward Islands and most of the Windward Islands from late September through November
The ENSO Alert System Status is an El Niño Advisory. El Niño conditions are present and expected to strengthen through the end of the year, with a 97% chance of persisting through early spring 2027.
Announcements in this issue
The bulletin carries three items alongside the forecast. A first ever standard operating procedure for coral bleaching monitoring has been launched, giving Caribbean practitioners a common method for recording bleaching as this event unfolds. Research on restoration stocks of a Caribbean coral species has found low levels of inherent resistance to stony coral tissue loss disease, a finding with direct consequences for how restoration programmes select and manage stock. CIMH and NOAA CRW are also calling for coral bleaching observations from across the region, which can be submitted through the links in the bulletin.
