The Mediterranean Sea has experienced surface temperatures consistently above the 1991–2020 average throughout 2024 and 2025, according to the Spanish State Meteorological Agency (Aemet). This prolonged period of elevated sea temperatures reflects widespread trends across European waters and highlights key concerns for marine climate monitoring.
Aemet reported via X, formerly Twitter, that "the Mediterranean Sea surface temperature has been above the average of the 1991–2020 reference period throughout both 2024 and 2025." Notably, "it only approached normal values briefly at the end of July and start of August and again in mid-October of both years." These fluctuations captured the few intervals when the Mediterranean's warmth briefly converged with long-term seasonal patterns.
International data confirm record ocean heat in 2025
Further insights arrived as the scientific journal Advances in Atmospheric Sciences published findings on Friday showing that the Earth's oceans stored more heat in 2025 than in any other year since modern records began. This marked the continuation of a trend, with nine consecutive record-setting years.
The research relies on datasets from leading international organisations, such as Copernicus Marine, China’s Institute of Atmospheric Physics, NOAA/NCEI (US National Centers for Environmental Information), and collaborative meta-analyses spanning Asia, Europe, and the Americas (CIGAR-RT). Collectively, these groups confirmed that in 2025, global Ocean Heat Content (OHC)—an essential indicator for long-term climate monitoring—reached its highest recorded value, supporting the case for ongoing ocean warming.
Regional variations in sea temperature
While Mediterranean waters exhibited persistent warmth, the study highlighted unequal heating across the globe. The most pronounced anomalies were seen in the tropical oceans, the South Atlantic, the North Pacific and the Southern Ocean, according to international monitoring bodies.
Meanwhile, around the Canary Islands in the Atlantic, temperature readings also generally exceeded the 1991–2020 average. However, colder-than-normal waters occurred in early March, from late September to mid-October, and in December 2025, reflecting significant seasonal variability within the region.
These ongoing deviations from historical sea temperature norms underscore the importance of sustained scientific observation and international data sharing for understanding climate dynamics in Europe and globally.