An intense polar air mass has triggered a cold wave across parts of Brazil, bringing freezing temperatures to the south and southeast on Monday [1].

This weather event is significant because it introduces the risk of frost, frozen rain, and snow in mountainous regions, potentially impacting agriculture and public infrastructure in the affected states [1, 2].

The cold front has been most prominent in the state of Paraná and the region of São Paulo [4, 5]. In Paraná, the intensity of the air mass led to a recorded wind chill of -7.5°C [1], a sharp drop that underscores the severity of the polar displacement. In Curitiba, temperatures were recorded at 2.7°C [1].

Meteorologists said that the polar air mass is displacing cold air deep into the south of the country [1, 4]. While the cold front is expected to lose some strength, cloudy skies and low temperatures are expected to persist in São Paulo [5].

Paula Nobre of Jovem Pan News said, "A onda de frio deve durar até quarta‑feira (13)." [6]

This forecast suggests that residents in these regions will face several days of extreme weather before temperatures begin to stabilize. The window of risk for frost and frozen precipitation remains open through Wednesday, May 13, 2026 [3].

“-7.5°C wind chill recorded in Paraná”

The arrival of an intense polar air mass in May indicates a significant atmospheric shift that can disrupt regional agriculture, particularly for crops sensitive to frost. The concentration of extreme lows in Paraná and São Paulo suggests a deep penetration of polar air, which often leads to increased energy demand for heating and potential transportation delays due to frozen road conditions in higher altitudes.