In statements to the Lusa news agency, meteorologist Elsa Vieira, from the IPMA delegation in the Azores, explained that the weather situation has been caused by "a mass of warm, humid air from the Southwest," which carries high levels of water vapour and relative humidity.

"This air mass has remained practically stationary over the archipelago, favouring the formation of fog or mist, especially in the areas of the southern coast of the islands," added the meteorologist.

Elsa Vieira added that the phenomenon "always worsens in the early morning hours, a period when visibility decreases significantly," affecting landing and takeoff operations at airports.

As daytime warms, conditions tend to improve in the afternoon, but visibility decreases again by the end of the day, according to the meteorologist.

IPMA (Portuguese Institute of the Sea and the Atmosphere) predicts that conditions will remain favourable for mist or fog to form throughout the week, especially on the south coast of the islands, though with longer periods of clear skies.

The atmospheric conditions in the Azores have had a strong impact on air operations, affecting hundreds of flights.