Rains lasting a few hours stopped São Paulo, the country’s main metropolis, entire neighborhoods punished in the Serra Fluminense, historic heat in the South, cities covered in hail and a tornado of rare strength in Paraná. Throughout the year, the climate made the news month after month in Brazil, with extreme events that left people dead, thousands homeless and damage spread across different regions of the country.
- Also read: What is an extratropical cyclone and how does it form? Understanding infographics
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The first major warning came in January, when a strong storm hit the city of São Paulo. The intense and concentrated rains caused flooding in avenues and train and metro stations, washing away cars and leaving part of the capital without electricity. The volume recorded in a few hours exceeded the total expected for the entire month, paralyzing public transport, worsening traffic and leading Civil Defense to activate, for the first time, a direct alert system on the population’s cell phones.
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In April, it was Rio de Janeiro’s turn to face one of the most critical situations of the year. Intense rains hit the mountainous region and caused Petrópolis to declare an emergency. In a single day, the accumulation exceeded the 300 millimeter mark in some places, causing landslides, flooding and damage to urban infrastructure. The impact of the rains extended to different regions of the state, from the capital to the Costa Verde, placing Rio under the greatest attention.
In February, Rio Grande do Sul faced an intense heatwave, with temperatures above 40°C in several cities in the interior. The prolonged heat has affected people’s habits, put pressure on water supplies, caused damage to landscapes and highlighted the difficulty cities face in coping with increasingly high temperatures.
Still in the South, the advance of violent storms has once again caused damage. In Erechim, northern Rio Grande do Sul, a strong hailstorm hit dozens of neighborhoods, injured hundreds and caused damage to schools, health facilities and public buildings. The city declared an emergency, suspended classes and had to shelter families who were unable to stay in their homes after roofs and structures were destroyed.
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Last week, the São Paulo metropolitan area once again faced an episode of extreme winds associated with the passage of an extratropical cyclone, which felled trees and interrupted services. With gusts approaching 100 km/h in parts of the capital, the storm left around 2.26 million properties without electricity in the metropolitan region – a number equivalent to around a quarter of customers – and also affected water supplies in neighborhoods that rely on pumping, in addition to causing flight cancellations in Congonhas and Guarulhos, impacting train traffic and leading to the temporary closure of parks and public facilities; Inland, there was a fatal landslide in Campos do Jordão, in the Serra da Mantiqueira.
The most extreme episode of the year, however, was recorded inside Paraná. A tornado of great intensity struck municipalities in the central region of the state, with a particularly serious impact in Rio Bonito do Iguaçu. The phenomenon left at least six dead, caused widespread destruction and forced thousands of people to leave their homes. Ranked among the strongest tornadoes ever recorded in Paraná, the event led to the declaration of a public calamity and mobilized a state and federal task force to assist victims and begin reconstruction.
Destruction in Rio Bonito do Iguaçu (PR)
The city was devastated by the cyclone
The year 2026 begins under the influence of a La Niña (ocean water cooling phenomenon) of low intensity, but with obvious signs of weakening throughout the summer. According to global climate models, the phenomenon is expected to ease in the first months of the year and give way to a period of neutrality in the Pacific in the first quarter, reducing the role of more defined global climate models and increasing the weight of regional systems in defining the weather throughout the year.
Even with limited intensity, La Niña can still disrupt the precipitation pattern. The World Meteorological Organization (WMO) estimates that there is about a 55% chance that this phenomenon will influence the global climate between December 2025 and February 2026. In Brazil, this trend is historically associated with increased precipitation in the North and part of the Northeast, while the South tends to record lower than average volumes. In the Center-West and South-East, the performance of regional systems begins to play a more decisive role during the rainy season.
— La Niña is currently acting, but already at a weak stage and with a tendency to weaken quickly. Neutrality should be established in the first quarter of 2026, estimates meteorologist Andrea Ramos.
La Niña weakens and neutrality gains ground
From late summer onwards, with the transition to ENSO neutral conditions – when there is neither La Niña nor El Niño – seasonal forecasts become more uncertain. Neutrality reduces the Pacific’s dominant influence on global atmospheric circulation and increases regional variability, giving cold fronts, troughs, areas of low pressure, and air masses greater weight in defining weather throughout the year.
— In neutral years, there is no dominant model controlling atmospheric circulation. The behavior of the weather is starting to depend much more on what is happening on a regional scale — explains meteorologist Cesar Soares, from Climatempo.
Even if advances in meteorology make it possible to identify medium and long-term trends, anticipating the weather a year in advance remains a challenge. The atmosphere responds sensitively to small variations in temperature, humidity, and pressure, limiting the ability of long-term models to accurately indicate precipitation, heat waves, or cold spells.
— Small changes today can generate completely different scenarios months in advance, making it impossible to predict exactly how many extreme events will occur or when they will occur — explains Marcio Bueno, meteorologist at TempoOK Meteorologia.
The influence of the oceans adds another layer of complexity to the projections. Phenomena such as El Niño and La Niña alter wind, temperature and precipitation patterns globally, but their intensity, duration and timing cannot always be anticipated. In Brazil, the temperature of the Atlantic also plays an important role in the evolution of the weather.
— Even subtle variations in sea surface temperature are enough to change the entire atmospheric scenario. In many cases, the Atlantic can weigh more than a weak El Niño or La Niña, points out Marcio Bueno.
What the models indicate for the Pacific in 2026
The most recent analyzes from the Columbia Climate School (IRI) indicate that there is a possibility of warming in the Pacific and the possible formation of an El Niño phenomenon in the second half of 2026, but the probability of this scenario does not exceed 50% and is still considered a distant trend.
Climate models also indicate that summer 2025/2026 could see drier periods in part of Brazil, as cold fronts tend to have difficulty progressing into the interior of the country, reducing the formation of organized rain systems, such as the South Atlantic Convergence Zone (SACZ) and moisture corridors. For fall, the trend is toward warming oceans, which can lead to above-average temperatures at certain times of the year.
In the area of extreme events, experts emphasize that tornadoes, severe storms and extratropical cyclones are not a direct consequence of La Niña or El Niño. These phenomena depend on short-term atmospheric conditions such as intense heat, high humidity and strong wind shear.
— What climatology allows is to identify more favorable periods for the appearance of these systems, and not to predict specific events. The tornado is an analysis of weather, not climate, says Cesar Soares.
From a climatological point of view, spring and summer continue to be the periods when the frequency of severe convective systems is highest in the country. Summer, which begins in late December, also sees the highest volumes of rain of the year and prolonged periods of heat.
In addition to climate behavior, 2026 will also be marked by important astronomical events.
- February 17 — Annular solar eclipse (ring of fire). It will not be visible in Brazil; the phenomenon can be observed mainly in Antarctica and partially in parts of Africa and South America.
- March 3 — Total lunar eclipse (blood moon). Partially visible in Brazil, with sightings also in parts of Asia, Australia, the Pacific Islands and the Americas.
- August 12 — Total solar eclipse. The band of totality crosses Greenland, Iceland, Spain and Portugal. In Brazil, the eclipse will be partially visible, including in northeastern areas.
- August 27 and 28 — Partial lunar eclipse. Partially visible in Brazil, in addition to the Americas, Europe, Africa and Western Asia.
With the start of the year still under the residual influence of La Niña and the expectation of neutrality for the following months, 2026 promises to be a year of climatic transition, marked by greater regional variability, constant attention to short-term extreme events and periods of heat throughout the calendar.
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