After a 2025 that went down in history in Brazil due to frequent incursions of polar air masses, episodes of extreme wind, and severe weather events distributed throughout the seasons, the year 2026 is predicted to be even more turbulent, with the presence of La Niña, the formation of El Niño, and the influence of other atmospheric and oceanic factors that may stand out during the year. This is according to Climatempo, a meteorological consulting company.
“The year 2026 will be marked by several atmospheric and oceanic phenomena and factors that will bring oscillations throughout the 12 months, making long-term forecasts difficult and requiring governments and companies to work with meteorological and climate monitoring and information in order to reduce risks and minimize impacts,” says meteorologist Vinicius Lucyrio from Climatempo, highlighting that the most vulnerable sectors are energy, supply, agribusiness, logistics and infrastructure, among others.
The intense heat recorded this summer is not expected to be limited to this season alone. The forecast is that 2026 will again see temperatures above the average recorded in the last two years. "The hot periods tend to be very hot, and the periods of unseasonably warm weather will alternate with heavy rains and a drop in temperature. The forecast is for alternating periods of higher temperatures and drier weather, even with heat waves, with wetter, cooler periods and heavy rains," anticipates Lucyrio.
The second half of autumn and the beginning of winter – between May and the beginning of July – will also be marked by temperature extremes, with significant drops in thermometers in the Central-South region of the country, including São Paulo, Minas Gerais, Rio de Janeiro, and all the southern states. Temperatures should remain lower until the second or third week of July, but from then on, the heat will prevail again, extending throughout the spring. In other words, the heat will advance before winter ends.
With La Niña reaching its peak intensity, characterized by the cooling of the waters of the equatorial Pacific Ocean, the year 2026 begins under the influence of climate variability patterns that alternate phases from one week to the next, such as the Madden-Julian Oscillation, in which there are phases with a greater propensity for the formation of heavy clouds and widespread rains during the Brazilian summer, and phases in which this condition is suppressed, bringing drier weather and intense heat.
Seasonal forecasting models indicate that until the end of summer, the rainy and heat wave phases will alternate, lacking the necessary regularity of rainfall during the wet season to safely replenish the reservoir levels of the Cantareira system and the hydroelectric reservoirs of the Southeast and Midwest subsystems, which account for 70% of the national hydroelectric generation.
In the Southeast and Central-West subsystems, there will be heavy rainfall in the Rio Grande and Rio Paranaíba basins, but alternating with heat waves. "The levels in this subsystem will gradually rise until the beginning of winter, but are not expected to reach ideal replenishment levels due to the lack of rainfall regularity," notes Lucyrio, mentioning that the same is expected to occur in the Cantareira water supply system in São Paulo.
At the end of summer and the beginning of autumn, partly due to the predicted warming of the Pacific Ocean within the period of climate neutrality, there is a possibility of an extended wet season above normal, with more regular rainfall, which could help replenish reservoirs.
During this period of neutrality, just like the Madden-Julian Oscillation, another pattern called the Antarctic Oscillation can also bring climatic variability throughout the year, potentially weakening or strengthening winds at high altitudes. In its positive phase, this oscillation is frequently associated with a strengthening of wind circulation around Antarctica, which tends to keep cold fronts more concentrated in the south of the continent, resulting in average or above-average temperatures in Brazil. In its negative phase, it allows polar air masses to advance more easily towards Brazil, resulting in sharp temperature drops, cold waves, and frosts, especially in the South, Southeast, and Central-West regions. Both oscillations are relevant throughout the year, but the Madden-Julian Oscillation has a greater impact during the wet season, while the Antarctic Oscillation has more noticeable effects during the colder season.
In mid-July, with the end of the neutral period and the formation of El Niño at the beginning of winter in the equatorial Pacific Ocean, the trend is for a turbulent period, outside of normal characteristics, in the second half of 2026.
August will be conducive to the start of heat waves with temperatures around 5°C above average, extending from September to October, months that should mark the gradual return of rainfall. In Matopiba, the forecast is for unseasonal rainfall in August and September, with considerable heat, which may mislead agricultural producers into planting, but rainfall is not expected to be regular during this period.
On the other hand, the incidence of intense heat waves due to the warming Pacific Ocean will be favorable for the ventilation and refrigeration sector, since the demand for fans and air conditioners in much of the country is expected to be high due to the unseasonal heat in the second half of the year.
In the Amazon region, especially on the Rio Negro in Manaus, the forecast is for a higher flood level than in 2025 and, in the second half of the year, a sharp drop in the river level. Even with these two extremes, it is unlikely that there will be problems with the circulation of vessels and the flow of production in 2026.
In Rio Grande do Sul and Santa Catarina, numerous atmospheric blocking patterns tend to cause rainfall well above average. There is a higher risk of extreme rainfall events starting in September, with the risk increasing in October and November. In addition to rain, there is a forecast of storms, with winds and hail, which may cause disruption to the population.
Receive the latest agriculture news by email
Receive the latest agriculture news by email
