The marine heatwave bulletin provides forecasts and analysis of marine heatwave events across the globe and throughout the year. Used datasets include observations (satellite sea surface temperature maps) and numerical model analyses (assimilating satellite and in situ observations) to derive marine heatwave forecasts for a 10-day period. This week’s forecasts were produced using as a comparison the marine heatwave situation on 08/07/2025.
Key Takeaways
- Overall decrease in marine heatwave activity in the Mediterranean Sea.
- Increasing marine heatwave intensity and extent in the Atlantic coast of France, the British Isles, and parts of the North Sea.
- Increasing marine heatwave intensity in Gulf of Mexico and south of Cuba.
- Decreasing extent and no change in intensity of the marine heatwave in the Indian Ocean.
European Zone
North Atlantic
The marine heatwave along the Atlantic coast of France, the British Isles, and parts of the North Sea is increasing in both extent and intensity, with the local emergence of severe and extreme categories.
Mediterranean Sea
The marine heatwave is decreasing in extent and intensity, shifting from strong and severe categories to moderate and locally strong categories.
Global ocean
North Atlantic
The marine heatwave stretching from eastern Florida to the central basin continues to persist in size, with an expansion of areas classified as strong and, in some places, severe and extreme.
Tropical Atlantic
The marine heatwave in the Gulf of Mexico and south of Cuba persists in extent and is increasing in intensity, with the emergence of strong and locally severe and extreme categories.
North Pacific
The marine heatwave in the central basin around 30°N is decreasing in area, but its intensity remains mostly in the strong category, with some moderate and severe categories still present.
The marine heatwave in the Sea of Japan is decreasing in extent, with its intensity generally shifting to moderate and strong categories.
Indian Ocean
The marine heatwave in the central basin is decreasing in area, with its intensity remaining in the moderate and locally strong categories.
Weekly Temperature Anomalies
13 – 19 July 2025
| North Atlantic | -2°C to >3°C |
| Mediterranean Sea | -1°C to >3°C |
| Tropical Atlantic | -2°C to 2°C |
| North Pacific | -3°C < à >3°C |
| Indian Ocean | -3°C to 2°C |
Access the Daily Global Physical Bulletin for a 9-day forecast here.
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Notes
Datasets and products :
Global Ocean Physics Analysis and Forecast (sea surface temperature) E.U. Copernicus Marine Service/ Mercator Ocean International. https://doi.org/10.48670/moi-00016
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