Inmet: weather forecast until Monday (July 6th)

The polar air mass affecting part of the country will cause temperatures to drop drastically this weekend, according to the National Institute of Meteorology (Inmet). On Saturday (July 4th), minimum temperatures could reach -3°C and -6°C in some cities in Rio Grande do Sul and Santa Catarina, where there will be conditions for widespread frost between dawn and the early morning hours. 

Minimum temperatures are expected to drop slightly further in areas of Mato Grosso do Sul, southern and western Goiás, Mato Grosso, Roraima, Acre, and southern Amazonas. The effects of this cold wave will also be felt in cities in the eastern part of the Southeast region. Strong winds will persist along the coast, especially off the coast of Rio Grande do Sul and Santa Catarina, which should keep the sea rough and create conditions for high surf along the coast of the southern states and the southeastern coast.

On Sunday (July 5th), the cold front weakens and temperatures begin to rise gradually; however, there will still be a chance of frost, especially in the mountainous areas of Rio Grande do Sul and Santa Catarina. Showers will be concentrated in the northern part of the North region and isolated rain showers along the coastal strip of the Northeast region. In much of the interior of the country, the weather remains dry. 

On Monday (July 6th), the formation of a new cold front should bring rain back to areas of the southern states of Brazil, when temperatures will drop again in some areas, especially in Rio Grande do Sul. In most of Brazil, the weather will remain stable with no rain forecast. Except for the northern part of the North region and coastal areas of the Northeast region, where showers are expected.

Northern Region

Between Saturday and Monday, hot and humid weather will continue with localized showers, accompanied by lightning and gusts of wind, mainly from the afternoon onwards. Rain is expected to affect the northern part of Amazonas, Roraima, northwestern and northern Pará, and Amapá. Minimum temperatures will continue to be influenced by the cold front covering the southwest of the region and will be around 13°C to 15°C. Maximum temperatures will range between 36°C and 38°C. Minimum air humidity will remain below 30% only in areas between Tocantins and southeastern Pará.

North East Region

Between Saturday and Monday, the chance of rain, even localized, is limited to coastal areas of the region. On Saturday and Sunday, for example, accumulated rainfall is forecast for the states of Ceará, Rio Grande do Norte, and Pernambuco. The weather remains hot and dry in the interior of the region, and the minimum air humidity, which usually occurs in the mid-afternoon, should remain between 30% and 20%, mainly in locations in the Northeastern Sertão region. Minimum temperatures should range from 9°C to 12°C, and maximum temperatures will be around 33°C and 35°C.

Midwest region

From Saturday to Monday, stable weather with no rain forecast will continue to prevail over the next few days. Maximum temperatures should rise in areas of Mato Grosso and Mato Grosso do Sul starting Saturday afternoon. The weather will remain predominantly sunny with few clouds. Minimum air humidity should vary between 20% and 30% in the mid-afternoon in the central-western part of Mato Grosso, as well as areas of Goiás and the Federal District. Minimum temperatures should be around 8°C to 12°C and maximum temperatures between 34°C and 36°C.

Southeast

On Saturday, isolated showers are expected along the coast of São Paulo state and from late afternoon in Rio de Janeiro, due to the arrival of humid winds from the ocean with the rotation of a post-frontal high-pressure system. Strong winds are also forecast along the coast of Rio de Janeiro, with a yellow warning in effect for the region. In the rest of the region, the weather will remain dry with variable cloudiness. Minimum temperatures will range between 5 and 7°C in southern Minas Gerais, the Paraíba Valley (SP), the São Paulo Metropolitan Region, the mountainous regions of Rio de Janeiro and Espírito Santo, and the Caparaó region of Espírito Santo. A temperature drop is also expected in much of the aforementioned regions, due to the proximity of a polar air mass.

Maximum temperatures will reach around 28°C in northwestern São Paulo and Minas Gerais, as well as the far north of Espírito Santo. On the coast of São Paulo, maximum temperatures are not expected to exceed 16°C. Relative humidity is forecast to be above 90% at the start of the day, decreasing to around 40% during the afternoon. In the coastal regions of São Paulo and Rio de Janeiro, humidity will remain high throughout the day.

On Sunday, there is still a possibility of isolated showers on the northern coast of São Paulo and along the coast of Rio de Janeiro, mainly until late morning. With the advance of the frontal system and the associated post-frontal high, isolated rain conditions will spread to the entire coast of Espírito Santo throughout the day. Minimum temperatures will be between 5 and 7°C in southern Minas Gerais, east-central São Paulo, the mountainous regions of Rio de Janeiro and Espírito Santo, and in the Caparaó region of Espírito Santo. Maximum temperatures will be around 30°C in the far northwest of São Paulo and the Triângulo Mineiro region. On the coast of São Paulo, maximum temperatures will begin to rise slightly, with values ​​between 18 and 20°C. Relative humidity values ​​are forecast to be similar to Saturday's.

On Monday, more stable atmospheric conditions will prevail across the entire region. The chances of rain will be reduced, and cloud cover will vary throughout the day. Minimum temperatures will remain low, with values ​​between 6 and 8°C in the mountain areas of all states. Maximum temperatures will continue to rise on the coast of São Paulo, reaching values ​​between 24 and 26°C. In northwestern São Paulo, maximum temperatures will remain around 30°C. During the afternoon, relative humidity may reach values ​​between 30 and 35% in the central-west of São Paulo.

South

On Saturday, isolated showers are only expected between the coast of Paraná and the northern coast of Santa Catarina, during the morning and afternoon. Due to the action of post-frontal high pressure, atmospheric stability conditions will prevail in most of the region. The rest of the region has reduced chances of rain and a forecast of varying cloudiness throughout the day. Minimum temperatures will be below freezing in the mountain ranges of Santa Catarina and Rio Grande do Sul, areas that also have an orange-level warning for frost. Maximum temperatures will be around 12°C in most of the region, except for the extreme northwest of Paraná, where maximums will be between 24 and 26°C.

On Sunday, the formation of a low-pressure system near the southern coast of Rio Grande do Sul will begin to bring new chances of isolated showers to the south-central region of the state, mainly from the afternoon onwards. The rest of the southern region will continue to have reduced chances of rain and variable cloudiness throughout the day. Minimum temperatures will remain low, with values ​​close to zero in the pampas region of Rio Grande do Sul and in the mountain ranges of Santa Catarina and Rio Grande do Sul. Maximum temperatures will begin to rise slightly, reaching around 16°C in most states. Only in the mountain areas and the pampas region of Rio Grande do Sul will the maximum temperatures not yet rise, remaining below 14°C. The extreme northwest of Paraná is still expected to have maximum temperatures between 24 and 26°C.

On Monday, the formation and passage of a new cold front associated with low pressure off the coast of Rio Grande do Sul will bring instability back to the region. More intense rainfall in the form of showers is expected, mainly between southern Paraná and northern Rio Grande do Sul. Minimum temperatures will be close to zero in the Rio Grande do Sul countryside. Maximum temperatures in the region will be below 14°C. The extreme northwest of Paraná will still see maximum temperatures between 24 and 26°C.