The intense polar air mass that brought São Paulo its coldest morning of the year, with the mercury falling to 9.4°C at the Mirante de Santana station, begins to lose its grip on central and southeastern Brazil from Wednesday. According to the National Institute of Meteorology, the cold air will recede gradually across the Centre-West and Southeast, where minima in southern Goiás, Mato Grosso and the Federal District will remain near 15°C only through Wednesday before rising. Yet the retreat is uneven: in the southern state of Rio Grande do Sul and neighbouring areas, low temperatures are expected to persist, while central Mato Grosso could see daytime highs of 38°C as the polar influence fades.

Even as the immediate chill subsides, a new cold front is forecast to advance from Friday, this time driven by a system moving over the Atlantic Ocean. Meteorologists tracking the front note that it will bring another sharp drop in temperatures to the South and Southeast, along with increased cloudiness and the risk of isolated showers. The pattern underscores the volatility of the austral winter onset: São Paulo, which shivered through a 9.4°C morning just two days ago, may see the mercury fall again by the weekend, albeit with less intensity than the current outbreak.

Viewed from Buenos Aires, the story is one of sustained cold rather than a brief shock. The Argentine National Meteorological Service forecasts that the city and its sprawling suburban belt will record minima of 6°C on Sunday and again on Tuesday, as a new mass of frigid air settles over the region. Unlike the Brazilian episode, where the cold is intermittent and punctuated by warm interludes, the Argentine capital faces a more persistent winter chill that is expected to hold into the start of the following week.

Analysts in London note that this dual pattern — a weakening but still active polar air mass over central Brazil coupled with a reinforcing front to the south — is typical of mid-year meteorological transitions in the Southern Cone. What marks this sequence as noteworthy is the speed of the temperature swings: within a matter of days, parts of the Centre-West lurch from near-freezing mornings to summerlike highs, while Buenos Aires endures a steady, unyielding cold. The forward outlook suggests that further polar intrusions are likely as the season deepens, with implications for agriculture in the grain belts of southern Brazil and the Pampas, where frost-sensitive crops remain exposed to abrupt thermal shocks.