In June, the Portuguese Navy Hydrographic Institute observed a significant increase in sea surface water temperature.

According to data provided by the Portuguese Navy, the temperature averages for June 2023, compared to the averages for the months of June in the period from 2000 to 2020, show this increase.

In Faro, the average temperature in June was 21°C, showing an increase of +1.4°C compared to the historical average of 19.6°C. In Sines, the average was 18.5°C, an increase of +1°C compared to the historical average of 17.5°C. In Leixões, the average temperature in June was 18.5°C, which represents an increase of +1.9°C compared to the historical average of 16.6°C.

In addition, in relation to the maximum values recorded in June 2023, compared with the averages of the months of June in the period from 2000 to 2020, there were significant increases. In Leixões, on June 20, the maximum temperature recorded was 21.0°C, an increase of +4.4°C compared to the historical average of 16.6°C, although lower than the record maximum of 22, 4°C recorded on August 14, 2004.

In Sines, on the 24th of June, the maximum temperature was 20.7°C, an increase of +3.2°C compared to the historical average of 17.5°C, but still lower than the recorded maximum of 23, 1 °C on August 19, 2016.

Finally, in Faro, on June 26, the maximum temperature was 24.4°C, a considerable increase of +4.8°C compared to the historical average of 19.6°C, although also below the record maximum of 26.6°C recorded on August 6, 2010.