Sea water temperatures reach record highs this summer

• The Dragonera buoy recorded the highest sea water temperature ever measured across the entire Puertos del Estado monitoring network, reaching 33.02°C on 5 August at 6:00 p.m.
• All buoys in the Levantine-Balearic basin, except the Valencia buoy, broke their own records for maximum water temperature.
• Record maximum temperatures were also recorded by the Basque buoys (Pasaia and Bilbao-Biscay) and the three Galician buoys (Estaca de Bares, Villano and Silleiro).

11 September 2026 (Puertos del Estado). Sea water temperatures reached new highs this summer, with an all-time temperature record recorded across the Puertos del Estado monitoring networks.

The Dragonera buoy recorded the highest sea water temperature ever measured across the entire Puertos del Estado monitoring network, reaching 33.02°C on 5 August at 6:00 p.m. This buoy has been equipped with a temperature sensor since 2006.

All buoys in the Levantine-Balearic basin, except the Valencia buoy, broke their own records for maximum water temperature:

• Mahón buoy: On 8 August at 5:00 p.m. local time, it recorded a water temperature of 32.36°C, a record for this buoy, which has been equipped with a temperature sensor since 2021.
• Tarragona Coastal Buoy: On 9 August at 5:00 p.m., it recorded 30.7°C, a record both for this buoy and for the Coastal Buoy Network, which has been collecting temperature data since 2013.
• Barcelona Coastal Buoy: On 9 August at 3:00 p.m., it recorded 30.5°C, a record for this buoy, which has been equipped with a temperature sensor since 2004.
• Tarragona buoy: On 13 August at 7:00 p.m. local time, it recorded 30.31°C, a record for this buoy, which has been equipped with a temperature sensor since 2004.
• Cabo de Palos buoy: On 21 July at 8:00 p.m., it recorded 29.77°C, a record for this buoy, which has been equipped with a temperature sensor since 2006.
• Cabo Begur buoy: On 16 August at 4:00 p.m., it recorded 29.18°C, a record for this buoy, which has been equipped with a temperature sensor since 2021.
• Cabo de Gata buoy: On 19 August at 3:00 p.m., it recorded 28.84°C, a record for this buoy, which has been equipped with a temperature sensor since 2001.

Record maximum temperatures were also recorded by the Basque buoys and all three Galician buoys:

• Pasaia II buoy: On 23 June at 7:00 p.m., it recorded 28.4°C, a record for this buoy, which has been equipped with a temperature sensor since 2022.
• Bilbao-Biscay buoy: On 12 August at 8:00 p.m., it recorded 25.27°C, a record for this buoy, which has been equipped with a temperature sensor since 2006.
• Estaca de Bares buoy: On 13 August at 7:00 p.m., it recorded 23.13°C, a record for this buoy, which has been equipped with a temperature sensor since 2001.
• Villano-Sisargas buoy: On 13 August at 4:00 p.m., it recorded 22.17°C, a record for this buoy, which has been equipped with a temperature sensor since 2001.
• Cabo Silleiro buoy: On 30 August at 9:00 p.m., it recorded 21.55°C, a record for this buoy, which has been equipped with a temperature sensor since 2001.

In addition, the Marine Climate Indicator for water temperature, based on buoy data, also shows that the summer of 2026 ranks among the warmest years in the period covered by the indicator, with temperatures above climatic averages during virtually every month of the summer. These values were driven particularly by data from the Levantine-Balearic and North Atlantic basins, where the buoys recorded the highest temperatures and the most records.

Another notable feature of this summer's measurements from the Puertos del Estado monitoring networks was the Málaga Coastal Buoy, which recorded its lowest water temperature for the month of August, measuring 15.6°C on Tuesday 25 August at 10:00 a.m. local time.

This was caused by a phenomenon known as upwelling, in which deeper, colder water rises to the surface. In this area, the phenomenon occurs when persistent westerly winds blow. The lowest temperature ever recorded by this buoy was 11.7°C, measured in January 2020.

PUERTOS DEL ESTADO MONITORING NETWORKS

Puertos del Estado operates an Offshore Buoy Network (or deep-water buoy network) comprising 15 monitoring locations, a Coastal Buoy Network with 14 monitoring locations, a network of 46 tide gauges along the Spanish coastline, and a high-frequency radar network comprising nine stations owned and jointly managed with other institutions.

All information is received in real time by Puertos del Estado, which is responsible for managing and distributing the data. https://portus.puertos.es/