A polar air mass is moving across Brazil, bringing cold weather to the South and Southeast regions and triggering forecasts of strong storms [1, 7].
This weather system creates a significant risk for agriculture in the South and disrupts urban infrastructure in major cities through intense precipitation. The sudden shift in temperature can impact public health and local logistics across several states.
The weather system, known as a frente fria, began affecting the region around Friday, June 15 [4]. Meteorologists said the front is expected to reach eight states, bringing a combination of intense rains and storms [4]. This movement follows earlier warnings issued as far back as May 27 regarding the arrival of polar air [6].
In the South, which includes Rio Grande do Sul, Santa Catarina, and Paraná, the temperature drop has been severe. Some areas are experiencing temperatures below 0 °C [5]. This freeze has put local crops on high alert, as sub-zero conditions can damage various agricultural yields [5].
The Southeast, including São Paulo and Rio de Janeiro, is also seeing a dominance of cold air [1, 7]. The system is creating a stark climatic divide across the country, with a temperature contrast of up to 30 °C between different regions [2].
Beyond the cold, the front is associated with significant weather disturbances. Forecasts indicate that Rio de Janeiro and Bahia are particularly vulnerable to strong storms [7]. These conditions are often exacerbated by the interaction between the polar air and warmer tropical moisture, a common driver of severe weather in the region.
Local authorities continue to monitor the advancement of the air mass as it settles over the southern capitals [1]. The persistence of winter-like cold during this period marks a sharp transition in the seasonal weather patterns for the region [1].
“The system is creating a stark climatic divide across the country, with a temperature contrast of up to 30 °C.”
The arrival of a polar air mass in June highlights the volatility of Brazil's winter transition. When polar fronts collide with tropical air, it creates the high-contrast temperature gradients and atmospheric instability that lead to the severe storms seen in Rio de Janeiro and Bahia. For the agricultural sector in the South, temperatures dipping below freezing pose a direct threat to crop viability and economic stability.
