Marine heatwave forecasts – August 9, 2025 – Re-posted from Mercator Ocean Bulletin

GLOBAL SST
  • Marine heatwaves are developing in the Tropical Atlantic, the Tropical Pacific, the North Pacific and the Indian Ocean regions.
  • In Europe, the marine heat wave off the Breton coast increases in intensity with strong category. The marine heat wave in North Sea and Norway Sea decreases in extent with moderate and strong categories.  
Category and geographical extent differences for 9 August, 2025. European zone. Credit: Mercator Ocean International

Tropical North Atlantic

The marine heat wave in the Gulf of Mexico, around Cuba and Florida increases in intensity with strong and locally sever categories

Tropical Pacific

The marine heatwave presents in the South China Sea increases in intensity, with moderate to strong categories. 

North Pacific

The marine heat wave presents in the centre of the basin at around 30°N and 60°N decreases in extent and increases in intensity off the Canadian coast with moderate to strong categories. The marine heatwave in the Sea of Japan and the Sea of Okhotsk decreases in intensity and in extent. The marine heat wave in the Sea Okhotsk have strong to sever categories.  

Indian Ocean

The marine heatwave in the central basin is decreasing in extent. The marine heat wave in the Bay of Bengal increases in intensity with mostly strong category. 

Mean sea surface temperature anomaly map for the week 3 to 9 August, 2025. Global Ocean. Credit: Mercator Ocean International
Mean sea surface temperature anomaly map for the week 3 to 9 August, 2025. Global Ocean. Credit: Mercator Ocean International

Mediterranean Sea-1°C à 1.5°C 
North Atlantic-2°C à >3°C 
North Pacific–1.5°C à >3°C 
Tropical Pacific –2.5°C à 2.5°C 
Indien Ocean -3°C < à 2.5°C