Heat wave will raise temperatures over 40 degrees Celsius at the end of winter in Brazil

El Niño and the climate crisis caused by the emission of greenhouse gases led the climate to extreme

Translated by: Ana Paula Rocha

Brasil de Fato | São Paulo (SP) |
The peak of the heat is expected to be felt across Brazil between the end of this week and the beginning of next. - Fernando Frazão/ Agência Brasil

Those who have already checked the temperature forecasts for the next few days in Brazil were surprised, as the estimate indicates that, even at the end of winter, some Brazilian cities may exceed 40 degrees Celsius (104 °F). The peak of the heat is expected to be felt across the country between the end of this week and the beginning of next week.

These predictions apply to all regions of Brazil, with none of them escaping the intense heat, according to MetSul Meteorologia, which described this event as "exceptional." Temperature records for September may be broken.

MetSul also informs that, although intense heat is not uncommon in these regions of the country in September, this situation represents a high risk due to the extreme severity of the predicted temperatures, requiring the attention of authorities.

Several Brazilian states will feel the impact of intense to extreme heat, with temperatures close to or above 40 degrees Celsius. It includes states such as Paraná, Mato Grosso do Sul, São Paulo, Mato Grosso, Rio de Janeiro, Minas Gerais, Goiás, Distrito Federal, Rondônia, Amazonas, Pará, Tocantins, Bahia, Piauí and Maranhão.

The worsening intensity of the heat wave affecting Brazil led the country’s National Institute of Meteorology (Inmet) to raise, on September 20, the alert level and include more states in the "great danger" category due to temperatures above average.

The heat wave began on September 17 and is expected to reach its peak the next weekend, with the possibility of still affecting countryside areas the following week. In some regions, temperatures are expected to reach 43 degrees Celsius.

Inmet's latest warning is classified as "red", indicating a situation of "great danger".

Public health and civil defense services list a series of tips and guidelines for people in places where heat and dry weather occur at the same time. The main recommendation is to stay hydrated, if possible, by drinking more water than usual. In addition to water, natural juices and coconut water are recommended. A good tip is to carry a water bottle to replace liquids when you are out and about.


The announcements released by Inmet coincide with an unusual heat wave in the Center-South region of Brazil. This heat wave will reach its highest point over the weekend, possibly setting records. The rise in temperatures is directly related to a significantly more intense El Niño this year, as well as the climate crisis, which is caused by the emission of greenhouse gases and makes extreme weather events more frequent.

Atmospheric blocks are common events, but the current concern is due to the following elements:

• Exceptional El Niño: This phenomenon is especially strong this year, warming the Pacific Ocean and inhibiting the influence of cold fronts in Brazil. It reinforces atmospheric blocking.

• Global warming: Experts point out that burning fossil fuels makes extreme weather events, such as cyclones and floods, more likely. It is alleged that the recent heatwaves in Europe would have been virtually impossible without climate change.

• September: September is naturally hot in Brazil’s central area due to the end of the dry period coupled with the increase in solar radiation.

Climate experts state that human activity has a significant influence on increasing the probability of these events occurring. They already say that, without global warming, some heat waves would be highly unlikely.

Among the many scientists investigating this topic, World Weather Attribution (WWA) performs attribution analyzes of global weather events. The WWA has already concluded that the link between extreme temperature and global warming is more evident than in the case of large storms or high volumes of rain.

According to the WWA analysis, the recent record highs of 40 degrees Celsius in the UK would be virtually impossible without global warming, as would the 2021 heatwave in North America.

Edited by: Nadini Lopes