It began on Wednesday (12) a wave of heat that hits the Southeast, Midwest and Northeast of Brazil. According to Climatempo, the forecast is that the phenomenon will continue until at least February 21.
Some weather models showed that in Rio de Janeiro, and in parts of Minas Gerais, Bahia, Pernambuco and Piauí, temperatures can reach almost 40ºC.
Based on projections from the University of São Paulo (USP) applied climatology table, which considers air temperature and humidity to inform the thermal sensation, the question arose: it is possible to have Thermal sensation of 70ºC Not Brazil?
Experts interviewed by CNN stated that, although the table presented the possibility, it is “Unlikely” That this happens. First, it is necessary to explain the formula used to calculate the thermal sensation.
Thermal sensation
“To calculate the thermal sensation, you have to consider temperature and humidity at the same time,” explains Mary Clara Sushaiakitime spokesman ok.
With only one of this information – whether only temperature or humidity – it is not possible to estimate the thermal sensation of a place.
“Almost always the highest temperature of the day happens in the afternoon. And during this period, usually there is a drop in air humidity, ”says JOSÉLIA PEGORIMMeteorologist of Climatempo.
For this reason, use the maximum temperature of one day, which usually occurs in the afternoon, with maximum humidity, which is usually recorded in the night/dawn, and say the thermal sensation of a place is wrong.
See Table:
“This table is a reference to evaluate the level of average discomfort that people would feel,” says USP professor and climate and environmental analyst at CNN, Pedro Côrtes.
With the understanding that the thermal sensation depends on the temperature and humidity of the air in the same place and time, we need to understand the influence of moisture in this formula. “If the temperature increases and moisture too, the sensation (thermal) is higher,” says Sassaki. But why?
Professor Côrtes explains that the hot, dry climate becomes “more tolerable” than hot and damp. In the case of places where moisture is high, such as a sauna, the feeling of heat will also be greater.
E OS 70ºC?
Despite the forecast of a heat wave for the coming days, with temperatures in the 40ºC, Pedro Côrtes said it was “unlikely” a thermal sensation of 70ºC.
“To have a thermal sensation of 70 °, the concomitant occurrence of a very high temperature and a very high humidity would be necessary,” he says. “This would even be possible, but it is very unlikely to happen, according to the weather forecasts for the coming days,” he concluded.
“Theoretically, yes (it is possible). But in practice, you don’t observe that. It is unlikely to have a moisture of 80% with temperatures of 39ºC, ”explains Pegorim.
Sassaki also explains that with open sky the trend is that the climate is drier. In case of cloudy days, moisture may increase, but the presence of clouds makes it difficult to rise. “I don’t know about any case that this happened (70ºC thermal sensation), with the parameters we use,” said Sassaki.
Experts also highlighted the individual aspect in the perception of the thermal sensation.
Josélia Pegorim explained that the higher the humidity, whether on cold or heat, “the more work for the body to maintain the temperature.” “When it is cold outside, it is your body who gives the heat,” he said.
Record chance
According to Climatempo, the four Southeast capitals have a chance to record heat records for the year 2025, and even summer (started in 2024).
In São Paulo the thermometers can reach 35 ° C, in Rio de Janeiro it is expected that the capital reaches 39 ° C by the end of the week.
For Belo Horizonte (MG) and Vitória (ES), the expectation is record between Thursday (13) and Friday (14). In BH, thermometers can reach 35 ° C, while in the capital of Espírito Santo the possibility is 39 ° C.
Heat wave
For the world weather organization, heat wave is configured when temperatures remain 5 ° C above average for five consecutive days.
During the heat wave it is important to maintain some precautions such as staying hydrated and avoiding long periods of sun exposure from 10am to 4pm.
It is also recommended to wear lighter clothes and apply sunscreen regularly. In cases of exhaustion and insolation, with nausea and dizziness, it is necessary to seek medical attention.
