Marine heatwave Bulletin Forecasts for 23 August 2025 Re-posted from Mercator Ocean Bulletin

Marine heatwave categories for 23 August, 2025. Global. Credit: Mercator Ocean International.

Key takeaways

  • North Atlantic (Europe region): The heatwave along the British Isles and south of the Brittany coast is increasing in both extent and intensity, with locally strong and severe categories observed.
  • Tropical Atlantic: The marine heatwave in the Gulf of Mexico and south of Cuba is increasing with the emergence of strong and locally severe categories.
  • Tropical and North Pacific: The heatwave in the central basin is increasing, with most of the area falling within the strong categories.
  • Indian Ocean: The marine heatwave in the Bay of Bengal is reducing in both extent and intensity.
Mean Sea Surface Temperature Anomalies for 16-23 August 2025. Credit: Mercator Ocean International.
Mean Sea Surface Temperature Anomalies for 16-23 August 2025. Credit: Mercator Ocean International.

Tropical North Atlantic

The marine heatwave in the Gulf of Mexico and south of Cuba persists in extent but decreases in intensity, with moderate and locally strong categories observed. The marine heatwave east of Florida is decreasing in extent but increasing in intensity, with the emergence of strong and locally severe categories. 

North Atltantic -2°C to 3°C 
Tropical Atlantic  -2°C to 2°C 
Tropical Pacific 0°C to 2°C 
North Pacific-3°C to 2°C 
Indien -3°C à >3°C