September heat with historical records

BarcelonaThe unbridled heat continues to set temperature records across the country. This Saturday, the highest maximum for a September since 1914 was recorded again at the Fabra Observatory, at 35.3 °C. With this historic value, there are now four records broken in the city of Barcelona since the beginning of the month. In Ponent, in the interior of the Ebre, and in regions like the Priorat, temperatures have reached or neared 40 °C again, with a new September record at 64 of the 128 #XEMA stations with more than twenty years of data.

And let's not forget the torrid nights. The Can Bruixa station (Barcelona) measured a minimum temperature of 26.5 °C this Saturday. It is the 62nd night of this 2026 that has not dropped below 25 °C (torrid night). It widely exceeds the 51 torrid nights of 2003, until now the record of the forty years of data (source: Meteocat).

The good news: everything indicates that this atypical heat will come to an end by the middle of the week. Starting Monday, cloudiness will increase with the approach of a colder mass that, on Wednesday, will bring thunderstorms and cause the thermometer to drop everywhere.

Sunday with more clouds, but still very hot

The entry of some cold air at altitude will cause more cloudiness to grow on Sunday, but this will not prevent the thermometer from continuing to rise. Early in the day, low clouds will appear along the southern coast, which will accentuate the feeling of mugginess. This cloudiness will dissipate quickly and give way to a radiant day. In the rest of the territory, there will be the passage ofthin clouds that will become thicker during the afternoon in the West. This cloudiness will slightly dampen solar radiation in some inland regions and thermometers may be held back a little more. It will be intensely hot but not as extreme as this Saturday's. Despite everything, it will still be possible to brush against 39 °C or 40 °C in the West and in the interior of the Ebro.

Meteocat has issued a danger warning for intense heat for Sunday that covers a large part of the regions of Ponent, Central Catalonia, the Pre-Pyrenees and, especially (in orange), the Ebro and southern regions.

Monday will be hot, but not as extreme. Starting Tuesday, temperatures in the Pyrenees will begin to normalize, and some of the first thunderstorms could appear in the Lleida Pyrenees. On the other hand, it will remain hot in the rest of the country, with values close to 33°C on the coast and 37°C inland. The change will arrive on Wednesday, as models indicate the arrival of a trough with cold air at altitude and strong thunderstorms in many places. With the arrival of the colder air mass, the environment will normalize and cool down, especially inland and in the Pyrenees.

The nights will also be cooler on the coast. Wednesday and during the early hours of Thursday, therefore, will be when there will be more instability, with downpours and strong storms in the northeast (with hailstorms), especially in the interior of the Girona regions, Central Catalonia and also on the coast.