General Elections, 4 and 25 October 2026

October marks a period of strong and direct El Niño influence in Brazil. Given the country’s vast territory, its effects vary considerably by region. While the South experiences severe storms and a risk of tornadoes, the Southeast receives above-average rainfall, whereas the Northeast, Central-West, and North face extreme heat and reduced precipitation (CNN Brasil, 2026). Accordingly, all three southern states were placed under severe-storm alerts, with wind gusts exceeding 90 km/h, large and heavy hail, and the possibility of tornadoes. On 4 October, a report published by the Brazilian Electricity Regulatory Agency (ANEEL) indicated that approximately 310,000 customers across Paraná, Santa Catarina, and Rio Grande do Sul were without electricity—affecting more than one million people (MetSul Meteorologia, 2026). 

On that same day, 4 October, Brazilian voters went to the polls to elect the president of the Republic, state governors, and members of parliament. As anticipated, several states were severely affected by storms, reducing voter turnout at certain times and making polling stations more difficult to reach. In São Paulo, for example, the city’s Climate Emergency Management Centre reported flooding in the state capital (Rádio Senado, 2026). In addition, according to the Regional Electoral Court of São Paulo (TRE-SP), at least 33 electoral zones in different parts of the state experienced power outages during election day (G1, 2026). 

The most serious situation occurred in Paraná, where 142 municipalities were under a red storm alert (Plural, 2026). The president of the Superior Electoral Court (TSE), Kassio Nunes Marques, identified the rainfall in Paraná as one of the main challenges of election day (Rádio Senado, 2026). Storm-related power outages affected approximately 94 municipalities and more than 223,000 voters. In Rio Grande do Sul, the Regional Electoral Court (TRE-RS) reported 56 locations without electricity in at least 19 municipalities early that morning. More than 240 polling locations had already been changed before voting began, leaving some voters uncertain about where to cast their ballots (Brasil de Fato, 2026). Similarly, in Santa Catarina, approximately 4,000 voters were affected by polling-location changes and had to travel to alternative addresses to vote (Eduardo, 2026). 

Under these circumstances, adverse weather led thousands of voters to postpone their arrival at polling stations, with turnout increasing sharply after 11:00 a.m. This resulted in queues at some polling centres, particularly where facilities were not prepared for the sudden influx. Nevertheless, the TSE stated that all polling stations operated normally despite the weather conditions. Brazil uses electronic voting machines, each equipped with sufficient battery capacity to complete voting and transmit results. Each machine has an internal battery that can last up to 10 hours and, when necessary, electoral offices can deploy backup batteries to maintain uninterrupted voting. Several states also established inter-agency monitoring arrangements. In Paraná, for example, the Paraná Environmental Monitoring and Technology System (Simepar) monitored weather conditions in partnership with the Regional Electoral Court of Paraná (TRE-PR) (Ritz, 2026). Using these data, the court was able to allocate resources and activate contingency plans. The electoral courts of the southern states also coordinated with one another to facilitate joint action in the event of climate-related emergencies affecting more than one state (Willerding Neto, 2026). 

Three weeks later, Brazil was preparing for the runoff amid an extratropical cyclone to form over the Atlantic Ocean and a cold front expected to intensify rainfall in the country’s South and Southeast regions (CNN Brasil, 2026), period when El Niño reached a temperature anomaly of 2.47°C, the highest on record for the month of October (INMET, 2026). As in the first round, warnings were issued for heavy rain, strong winds and hail. The Superior Electoral Court (TSE) had established a National Climate Situation Room for the 2026 elections, bringing together the TSE, 27 Regional Electoral Courts (TREs) and six partner institutions to identify risks that could disrupt voting. In the days preceding the election, the Situation Room closely monitored weather conditions in Rio Grande do Sul, Santa Catarina, Paraná, São Paulo and Minas Gerais, where rainfall was forecast. It also monitored fires in the North and Northeast regions (TSE, 2026). 

On election day, 25 October, heavy rainfall affected voters, particularly in the South. In Paraná, around 3,200 voters were assigned to different polling locations after rain hit the state in the two days before the election. In Barracão, where schools sustained severe damage, voting was moved to a safer location directly opposite the original site (CNN Brasil, 2026). Across Paraná, eight polling-location changes had been recorded in seven cities between the first and second rounds (O Globo, 2026). A polling location in the state capital, Curitiba, was also relocated. Rain blocked three roads in Paraná on election day, prompting the Federal Highway Police (PRF) to map alternative routes to help voters reach the polls (Jornal de Brasília, 2026). In São Paulo, the Regional Electoral Court (TRE-SP) reported that polling locations had been relocated in Itapevi. A relocation was also announced in Itupeva but was later cancelled after the rain stopped (Terra, 2026). In Santa Catarina, flooding required more than 600 voters to use a different polling location (CNN Brasil, 2026). Voters were advised to check their assigned locations through the TSE’s app, called e-Título. The Regional Electoral Court of Paraná (TRE-PR) also sent WhatsApp messages to notify voters of changes (CNN Brasil, 2026). 

Amid these disruptions and relocations, Flávio Bolsonaro’s campaign requested an extension of voting hours in Paraná, Santa Catarina and São Paulo because of the rain (CNN Brasil, 2026). Despite the numerous polling-location changes, no official figures were released on the number of voters unable to vote because of weather-related disruptions. Ultimately, the Supreme Federal Court (STF) granted a two-hour extension nationwide in response to voter transport difficulties reported by both presidential campaigns, many of which were unrelated to weather conditions (STF, 2026). 

Author: Gabrielle Balestra