Marine heatwave Bulletin
Forecasts for 6 September 2025​

European Zone

 

 

North Atlantic

The marine heatwave off the coast of Portugal to the British Isles no longer affects the area.       

Mediterranean Sea 

The marine heatwave in the western basin is decreasing in intensity and extent, with only a few moderate areas remaining. The extent of the marine heatwave in the eastern basin increases, with moderate and strong categories still present.

Global Ocean

 

Tropical Atlantic

The intensity of the marine heatwaves around Cuba and in the Gulf of Mexico increases and are now mainly in strong to severe category. The marine heatwave in the center of the basin around 60°W is decreasing in intensity and is now mostly in moderate category, with strong category locally.

North Pacific 

The area of the marine heatwave covering almost the entire basin is decreasing. The central and western parts of the basin are moving from severe, strong and moderate categories to areas free of marine heatwaves and areas in moderate and strong categories. The intensity of the marine heatwave band centred on 30°N is increasing, with the development of strong categories. Between 150°W and 120°W, the extent and intensity of the marine heatwave are increasing, affecting the entire zone in moderate, strong and severe categories.  

The Sea of Okhotsk is free of marine heatwaves. In the Sea of Japan, the situation remains stable, with moderate and strong categories, and locally severe.

In the East China Sea and the Yellow Sea, the intensity of the marine heatwave increases, with the development of severe categories, the rest of the area being mainly in strong category. 

Indian Ocean

The marine heatwave around 0° is decreasing in both intensity and extent, and is now mostly in moderate category, with strong category locally.