Spain faces first heatwave of the summer with temperatures set to reach 45°C and tropical nights

Arrival of the Saharan air

A powerful anticyclonic ridge settling over southern Europe, combined with a possible cut-off low (DANA) west of the Iberian Peninsula, is channelling extremely hot and dry Saharan air towards Spain. The State Meteorological Agency (AEMET) and Catalonia's Meteocat both warn that the episode will begin on Sunday 21 June, the summer solstice, and persist at least until Tuesday, possibly Wednesday. Dust-laden calima will accompany the heat, worsening conditions and contributing to tropical and even torrid nights.

We are likely facing the first heatwave of this summer. Temperatures will be between 5 and 10 degrees above normal for this time of year, and in some parts of the northern half of the Peninsula they could exceed normal by more than 10 degrees.

Where the mercury will peak

The interior river valleys will bear the brunt. Forecasts show 36-38°C already on Saturday, with a sharp jump on Sunday when 40°C will be generalised in the Ebro, Guadiana, Tajo and Guadalquivir valleys. Bilbao could record 42°C on Sunday, potentially the highest June reading in the city since 1950. By Tuesday the worst is expected in Extremadura, where Badajoz may hit 45°C. Other hotspots include the valleys of the Ebro and the northeastern depressions, where 38-40°C is forecast, and locally 44°C in the Guadalquivir and Guadiana basins on the peak days.

Nights that offer no relief

Minimum temperatures will stay above 20°C across large parts of the country, with tropical nights forecast for the Mediterranean coast and inland areas alike. In provinces such as Jaén, Ciudad Real, Córdoba and Almería the night-time mercury may not drop below 25°C, meeting the definition of a torrid night. Meteocat has highlighted that suspended dust will reinforce the phenomenon.

We are facing the first heatwave of the summer, especially inland, since we expect the thresholds to be exceeded at least from Sunday to Tuesday.

Alerts and new health thresholds

AEMET has issued yellow and orange warnings for maximum temperatures on Friday for Andalusia, Aragon, the Balearic Islands, Catalonia, Extremadura, Madrid, Navarre, the Basque Country and La Rioja. Storm warnings are also in place for parts of the north and centre on Friday. The Ministry of Health’s heat-health system, which factors in a 72-hour window of persistent heat and its link to mortality, has placed several zones at alert levels 2 and 3. In Catalonia, Meteocat has activated the year’s first “dangerous meteorological situation” for heat, now based on updated criteria: the reference period for calculating local thresholds has been extended from 10 to 15 years of data, and a 40°C cap has been introduced in towns such as Vinebre, Térmens and Ascó where the computed threshold would otherwise be even higher.

Warnings also for storms and fire risk

While the heat dominates, Friday will also bring scattered thunderstorms over the Cantabrian Mountains, the northern and eastern parts of Castile and Leon, the Iberian and Subbetic ranges, Navarre and La Mancha, with warnings in La Rioja, the Basque Country, Castile and Leon, Cantabria and Castile–La Mancha. The Civil Protection agency has issued an alert for a raised risk of forest fires. Authorities are urging the public to follow forecast updates and take precautions during the central hours of the day.