Detailed forecast: winter 2026 begins on Sunday with the first cold wave and impact of El Niño in Brazil
The coldest season of 2026 will officially begin at 5:24 am next Sunday, the 21st, according to Brasília time, marking the winter solstice and the longest night of the year. However, low temperatures already promise to be intense in the first days of the new season, significantly affecting the Center-South of Brazil.
Climatempo projections indicate that the initial period of winter will present greater cold intensity, accompanied by above-average precipitation in the South region and atypical rains for the season in areas of the Southeast and Central-West.
In contrast, the North and Northeast regions must experience a predominantly arid climate with high temperatures.
The month of July is considered the most rigorous of the season. The expectation is for two powerful incursions of cold air, predicted for the middle and end of the month, which could cause frosts and temperatures below zero in part of the South and certain areas of the Southeast.
One of these polar fronts has the potential to bring freezing air to locations such as Goiânia (GO), Brasília (DF), the north of Minas Gerais and the south of Bahia.
Although it is a rare phenomenon, the occurrence of snow is more likely in the mountainous regions of Rio Grande do Sul and Santa Catarina, especially during the beginning of winter and throughout July.
However, the first episode of intense cold is scheduled to precede these dates, with a robust polar air mass expected to cross the interior of Brazil between June 22nd and 30th.
This icy current is expected to impact the South region, sectors of the Southeast and Midwest. Additionally, the same cold air has the potential to generate cold in Rondônia, Acre and the southern portion of Amazonas.
“The first moments of winter tend to be characterized by a greater occurrence of cold periods. During this time, masses of polar air should move more regularly across the national territory, even reaching parts of Northern Brazil and causing sharp declines in temperatures”, details César Soares, meteorologist at Climatempo.
In the second half of August, there is a reduction in the intensity of polar air masses, resulting in an increase in temperatures, which in many cases will exceed historical averages.
Significant increases in heat are projected for August, covering the Central-West, Southeast, North and Northeast of the country.
With the arrival of September, in the final weeks of winter, there is a greater probability of heat waves occurring, especially in the Central-West, North and Northeast regions.
“In the final phase of winter, notably from the second half of August onwards, the severity of the cold decreases. The expectation is that temperatures will become milder and, in certain locations, even exceed the usual climatological average for this period”, adds meteorologist César Soares.
As for precipitation, the most relevant scenario remains in the south of the country. The greater frequency of cold fronts will contribute to higher-than-standard humidity, with southwestern Paraná likely to experience rainfall significantly above average.
However, predicted storms tend to be localized, without the vast coverage area observed in 2024.
The Southeast and Central-West regions, typically dry during the winter, may record episodes of sporadic and unusual rain at various points throughout the quarter.
Despite this, most of these areas are expected to experience numerous days of low humidity and considerable temperature fluctuations between the morning and afternoon periods.
On the other hand, the extreme north of Brazil and the eastern portion of the Northeast are expected to have a more arid climate than usual. This condition, combined with high temperatures, increases the risk of forest fires, especially in the area known as Matopiba, which encompasses parts of Maranhão, Tocantins, Piauí and Bahia.
The El Niño phenomenon, which officially established itself in the first week of June, has a notable influence on weather conditions, especially in the final stage of winter. El Niño is known for altering rainfall and temperature regimes in several regions, and its intensification could mean a reinforcement of drought trends in some areas and rainfall in others, as seen in past events.
Characterized by the warming of the waters of the Pacific Ocean, El Niño is rapidly strengthening, with the potential to reach strong to very strong intensity in the following months.
Detailed forecast for the month of July
- July stands out as the period of greatest cold intensity of the winter, with the expectation of two robust polar air masses, one in the middle and the other at the end of the month. These fronts should reach the South, Southeast and Center-West, with the possibility of extending to the north of Minas Gerais and the south of Bahia.
- The South region will face days of severe cold, with negative temperatures in higher altitude locations. The mountains of Rio Grande do Sul and Santa Catarina may record snow.
- Precipitation in the South is expected to exceed the average, especially in the southwest of Paraná. For other areas of Brazil, the general climate will be drier, with occasional rains.
- The Midwest and the interior of the Northeast will have hot days, marked by significant temperature variations between the morning and afternoon.
- In Rondônia, Acre and the southern portion of Amazonas, there is a possibility of cold weather throughout the month.
What to expect from the weather in August
- In the second half of August, the intensity of the cold decreases, and temperatures begin to rise in the Central-West, Southeast, North and Northeast, with the possibility of heat peaks in certain locations.
- A cold front of continental origin is still forecast to advance through the interior of Brazil, bringing precipitation to the Southeast and Center-West.
- The South region will continue to experience more regular rain, but the probability of extensive frosts is reduced compared to July.
- The predominance of dry air in much of the country increases the risk of fires, especially in Matopiba and in regions of the Center-West and North.
- Rondônia, Acre and southern Amazonas may still experience episodes of cold weather.
The weather characteristics of September
- September, the last month of winter, will present temperatures above average in much of the territory. The risk of heat waves intensifies, especially in the Central-West, North and Northeast.
- The rains will begin a progressive return in the Central-West and Southeast, while the South will remain with humidity above normal.
- The North and Northeast will maintain a predominantly dry climate. In Matopiba, the arrival of rain may be delayed compared to expectations for the beginning of spring.
It is possible to analyze climate projections for the winter of 2026, with particularities in each region of Brazil, according to upcoming information.
Expected weather conditions for the South region
The southern area of Brazil is expected to experience a winter with more precipitation than usual. The cold period, in turn, tends to be less prolonged compared to May and June, a direct reflection of the greater incidence of rain.
General temperatures in this region are expected to remain close to the seasonal average. The occurrence of extensive frosts and even snow is a possibility for higher altitude areas, both in the opening week of winter and during the month of July.
In the capitals Porto Alegre (RS), Curitiba (PR) and Florianópolis (SC), days of intense cold will alternate with periods of rain throughout the quarter.
Panorama of winter in Southeast Brazil
Precipitation in the Southeast is projected to remain close to the average in Minas Gerais and Rio de Janeiro. In the center-south of São Paulo, above-usual volume is expected, while Espírito Santo is expected to record below-average rainfall.
In most of the Southeast, temperatures will remain high, exceeding normal levels for the season.
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Cities such as São Paulo (SP), Belo Horizonte (MG) and Rio de Janeiro (RJ) may experience low temperatures at the beginning of winter and during July, with a risk of frost at higher altitudes, before heat returns in the final weeks of the season.
Climate conditions for the Midwest
Rainfall in the Midwest is expected to remain close to average across most of the region. However, there is the possibility of atypical precipitation at different times throughout the months.
The heat will be predominant and above average, especially in the central portion. Cities such as Brasília (DF), Goiânia (GO) and Cuiabá (MT) may feel a temporary cold in June and July, when polar air reaches the region, before temperatures rise in August.
Winter in the Northeast: forecasts and particularities
In the Northeast region, winter is characterized by being a dry and hot period. Precipitation tends to be below average across much of the territory, with greater intensity in the east.
Temperatures will continue to be above the usual standard, especially in Maranhão, western Piauí and western Bahia. Cities like Recife (PE) and Salvador (BA) will experience warm days and more stable weather conditions.
São Luís (MA), located in the extreme north of the Northeast, will see a decrease in rainfall as winter progresses.
Climate scenario for Northern Brazil
After an autumn marked by abundant rain, the North region enters its driest phase of the year, with rainfall expected to be below average across almost its entire length.
Heat will be the dominant characteristic of this period, potentially exceeding the historical average by more than 1°C, especially in the south and east of Pará and Tocantins.
Belém (PA) and Manaus (AM) may still record some rain at the beginning of winter, with a tendency to reduce in the following months. However, Rondônia, Acre and the southern portion of Amazonas are subject to cold episodes, influenced by cold air masses moving from the South.
Anticipating conditions for the coming days
This Friday, a cold front will move through the South Region, increasing the possibility of intense rain, thunderstorms and strong winds, especially in Rio Grande do Sul, Santa Catarina and Paraná.
Unstable weather conditions will begin to strengthen in the early hours of the day in the west and south of Rio Grande do Sul, progressing throughout the afternoon and night to other areas of the region, covering the west of Santa Catarina and the southwest and central-south of Paraná.
There is a likelihood of isolated storms, with rainfall of moderate to heavy intensity at certain times.
On Saturday, the 20th, the rains will lose intensity in Rio Grande do Sul, but are still expected in parts of Santa Catarina and Paraná, particularly in the north and east of Paraná.
The arrival of a colder air mass could result in sunrises with temperatures close to 3°C on the border with Uruguay and in the mountainous regions between Rio Grande do Sul and Santa Catarina. The Gaúcha Campaign also has a chance of recording frost.
In mountain areas, maximum temperatures are expected to remain low, without exceeding 10°C in some locations.
In the Southeast, the cold remains a point of attention, especially in elevated regions. For this Friday, most of the area will have stable weather, with skies varying from partly cloudy to cloudy and mild temperatures at the beginning of the journey.
In the mountains of São Paulo, Minas Gerais and Rio de Janeiro, thermometers can approach 4°C. The cold will also extend to the south of São Paulo and the south of Minas Gerais, with minimum temperatures varying between 5°C and 10°C.
During the night, the arrival of the cold front may generate isolated rain in the south of São Paulo. On Saturday, precipitation expands across the state of São Paulo and there is a chance of reaching the south of Minas Gerais and Rio de Janeiro.
For the Central-West, Friday will be marked by increased cloudiness and the occurrence of rain in Mato Grosso do Sul and Mato Grosso. The instability, originating in Paraguay, has the potential to cause heavy rains and thunderstorms, especially in Mato Grosso do Sul.
On Saturday, a mass of cold air will begin to influence Mato Grosso do Sul, reducing cloud cover in certain locations, but still with the possibility of isolated rain in the north and east of the state.
The cold will also be more present in the southern and western portions of Mato Grosso do Sul, with minimum temperatures varying between 8°C and 10°C.
In the North region, the rains will persist distributed over a large part of the territory. Roraima and Amazonas are expected to experience thunderstorms this Friday, and this situation will repeat itself on Saturday in areas of Acre, Amazonas, Rondônia, Pará and Amapá.
Tocantins will have a drier climate, with little cloud cover and intense heat. The highest maximum temperatures are expected for Tocantins and southeast Pará, with records between 34°C and 38°C.
In the Northeast, precipitation will be concentrated predominantly on the coast of Bahia, in Sergipe, Alagoas and in the central-eastern portion of Pernambuco this Friday.
Furthermore, there is a forecast of isolated rains in Maranhão, Piauí, Ceará, Paraíba, Rio Grande do Norte and the northeast of Bahia.
The interior of the Northeast will remain drier, particularly in the center-west of Bahia and in the southern portions of Maranhão and Piauí.
Chapada Diamantina, in Bahia, will have cold mornings, with minimum temperatures between 8°C and 10°C.
