An expansive high‑pressure system that has baked much of the western Mediterranean for over a month began to weaken on Sunday, as a deep low over Scandinavia drove cold, unstable air across northern and central Europe. The resulting clash of air masses triggered violent thunderstorms, large hail and flash flooding from northern Italy to southern Sweden, while Algeria, central and southern Italy, and the Levant continued to swelter in record‑breaking temperatures.

According to Algeria’s national weather office, the ‘thermal dome’ responsible for the prolonged heatwave is expected to begin a gradual retreat by 26 July, after days that have seen temperatures described as record‑breaking compared with seasonal norms. Parts of the country’s northern wilayas and oasis regions have been experiencing extreme heat for several consecutive days, in a wave that forecasters say is notable for its geographic spread and duration, recalling the record summers of 2021–2023. In Rome and Florence, thermometers again reached 37°C on Sunday, while Sicily and Sardinia exceeded 40°C. Moscow remained under an orange heat alert, with daytime highs of 30°C, and Mexican health authorities warned against outdoor activity as temperatures in Monterrey topped 40°C during the canícula.

The abrupt transition was most dramatic in the north. Swedish meteorologists reported that high‑summer heat had ended, with temperatures falling to 15–20°C countrywide and no return of warmth expected in visible forecasts. SMHI issued yellow warnings for torrential rain across Halland, Småland, Öland and parts of Skåne, where 30–40 mm of rain could fall in a short period, risking basement and drainage flooding. On Öland, winds gusting to 22 metres per second were forecast overnight into Monday, compounding hazards for tourists at the height of the holiday season. Farther north, the mining town of Kiruna recorded its coldest July night since 1987, with a low of 0.5°C. In Italy’s northern provinces, thunderstorms brought hailstones up to 9 cm in diameter that damaged vehicles and buildings in the Ferrara area, and a sharp temperature drop of up to 6°C gave relief from the oppressive heat. The Emilia Romagna region was placed under a yellow alert for Monday due to the risk of further strong storms.

In the southern hemisphere, a more typical winter pattern held in Australia, where the Bureau of Meteorology warned of dangerous surf along south‑east Queensland, with waves reaching 5.75 metres near Brisbane and a damaging‑surf warning in place between Moreton Island and the New South Wales border. That system was expected to begin easing on Monday, but residual large waves posed a continuing risk.

Meteorologists across affected regions cautioned that the unsettled conditions could persist for several days. Italian models suggested that the Azores anticyclone would eventually stabilise the weather and bring more typical seasonal temperatures, but for now, authorities maintained widespread yellow and orange alerts for heat, storms and flooding.