The weather of Thursday, August 20, 2026 will come with two faces. The entry of a front from the north will break stability in a large part of the Peninsula, while the heat will continue to tighten along the Mediterranean and in the Balearic Islands. The day will combine storms and high temperatures on a map that will change a lot between regions.
Cold air at altitude and a short wave will reinforce the instability. The northern third will have very cloudy or overcast skies and showers that can be strong and persistent. In the east and on the Balearic Islands, clouds will also grow, with storms that could deliver hail. The most serious risk will be concentrated in interior areas from the north, southeast and south of the archipelago.
Outside of these areas, intervals of medium and low clouds will dominate, although some isolated showers or storms are not ruled out. In the Canary Islands, cloudiness will be concentrated in the north and the south will maintain clear skies. Mists and fog banks may appear in the interior of the Cantabrian Sea. The evolution during the afternoon will be decisive to measure the intensity of showers.
The distribution of instability
The AEMET places the main focuses in the northern interior, the southeast of the peninsula and the south of the Balearic Islands. There the showers may reach very strong intensity, with gusts of wind and hail. In the southeast there is also the possibility of large hail occasionally, an episode that will have its greatest risk in areas where clouds develop. The forecast is reminiscent of other hail warnings recorded this summer. The size of the ice will be the most delicate factor in the most developed nuclei.
The front will also leave very cloudy or overcast skies in the northern third. Showers may be persistent and maintain stormy activity. In the rest of the Peninsula, the forecast opens the door to occasional rainfall, with more uncertainty as we move towards the center and west. The AEMET contemplates fog banks in the Cantabrian interior, at the beginning of the day. That forecast has already described days with contrasts between heat and showers. Instability will spread unevenlywithout affecting all provinces equally.
Thermal drop off the coast
Maximum temperatures will drop in almost the entire Peninsula and the decrease will be notable in the northeast. The minimums, on the other hand, will rise in some parts of the Mediterranean coast. On Thursday only the Mediterranean and the Balearic Islands will be able to exceed 35 degrees and register nights with more than 20. Thermal relief will be uneven and will be outside the coastal areas that maintain heat. A previous episode of intense heat showed a similar distribution between the interior and the coast.
Castelló de la Plana will reach 40 degrees, with 38 in Lleida and València, and 37 in Alicante, Murcia and Palma. Girona will reach 35. In the interior, Albacete and Badajoz will mark 32 and 33, while Madrid will remain at 30. In the north, Bilbao will have 25, Santander 23 and Oviedo 20. Maximum temperatures of 40 degrees appear again on the AEMET maps, although the territorial distribution will be different this Thursday. The Mediterranean coast will retain the highest record.
The wind will blow from the west and will be moderate in general. The storm may intensify in the Ebro valley and the west will do the same on the coast of the Alboran Sea. In the southeast and the Balearic Islands, the southwest will leave very strong gusts, while at the last few hours a strong north wind could enter the Ampurdán. The Canary Islands will maintain moderate trade winds. The wind will add another element of attention in areas where gusts and showers coincide.