Although nighttime temperatures have notably dropped in several Gipuzkoan towns, the oppressive heat will persist until Friday. According to Euskalmet, a air mass from the Sahara, southerly winds, and the Foehn effect are responsible for these high temperatures, which have broken historical May records.

On Wednesday and Thursday, maximum temperatures will exceed 30ºC on the coast and reach 34ºC inland. Consequently, Euskalmet has issued a yellow alert for persistent high temperatures. The thermal relief will arrive when the wind shifts to the west and cloud cover helps dissipate the mugginess.

The night of Monday to Tuesday saw a significant drop in minimum temperatures along the coast, averaging 10 degrees less, with 18.5ºC recorded on Santa Clara island and 17.5ºC in Higuer. However, daytime highs will again approach 31ºC on the coast and 34ºC inland.

Finally, a thermal decrease will be noticeable on Friday, with the wind veering west and cloud cover expected. This will lead to milder temperatures on Saturday and Sunday, around 24ºC maximum and 17ºC minimum.

Meteorologists explain that the heat is primarily caused by southerly winds from the Sahara and insolation, meaning a lack of clouds. Additionally, the Foehn effect is occurring, a phenomenon where a humid air mass rises over a mountain and descends on the other side as a much warmer, dry wind.