Inmet: weather forecast between October 13th and 17st, 2025

The National Institute of Meteorology (INMET) predicts a week marked by climatic contrasts across Brazil's regions. Between October 13 and 17, 2025, the advance of cold fronts is expected to bring heavy rains and a risk of thunderstorms in the South and Southeast, while the Northeast and parts of the Central-West remain dry and humid, potentially reaching critical levels below 25%. In the North, instability remains active, with significant rainfall accumulations in areas of Amazonas and Acre.

Na Northern RegionAreas of instability are expected to be concentrated in the western portion, especially in Amazonas, southern Roraima, and Acre. Rainfall may occasionally exceed 120 mm, but accumulated amounts over five days are unlikely to exceed 20 mm in most of the region. Generally, rain will be expected in practically the entire northern region, with the exception of the last day of the week, when rainfall is more prevalent in Amazonas. Low relative humidity is expected in the far north, encompassing Amapá and northern Pará, which could reach levels of up to 25%.

In much of the North East Region No rain is forecast for this week, with accumulations of up to 5 mm (light rain or short bursts) due to isolated rainfall in parts of the eastern coastal strip that stretches from Rio Grande do Norte to southern Bahia. Furthermore, low relative humidity levels are expected across most of the region, from the hinterland to the interior, especially in Piauí, western Bahia, much of Ceará, western Paraíba, and Rio Grande do Norte, where values ​​will be below 25%, occasionally falling below 20%. Conversely, the entire coastal strip is expected to experience RH levels around 50%.

Na Midwest region, evenly distributed rainfall is expected throughout the region during the first few days of the week, with low accumulations not exceeding 10 mm over the five-day period. In some specific regions, there is a possibility of more significant rainfall, with total accumulations around 20 mm. In other areas of the Central-West region, low accumulations are expected, with quick and localized showers. Also noteworthy is the forecast for relative humidity around 50% during the week, mainly in Mato Grosso do Sul and the southern portion of Goiás and Mato Grosso. However, the rest of Goiás and the Federal District will continue the week with low RH during the hottest part of the day, falling below 30% starting on the 15th.

For Southeast, the forecast indicates rain for this week, especially in São Paulo, southern Minas Gerais, the mountainous region of Rio de Janeiro, and southern Espírito Santo. The advance of a cold front favors accumulations of up to 100 mm, mainly in areas on the border between São Paulo and Paraná and Minas Gerais. However, rainfall distribution indicates accumulations of around 20 mm in most of the Southeast region. The possibility of localized thunderstorms with lightning, gusty winds, and the possibility of hail on the 14th cannot be ruled out. On the other hand, in northern Minas Gerais, the forecast is for no rain, resulting in a drop in relative humidity, falling below 25% and potentially below 20% in the extreme north of the state on Friday, October 17th.

For South, the week begins with the removal of the cold front that acted over the weekend, and a reduction in the atmospheric condition of heavy rainfall, favoring low accumulations at the beginning of the week followed by the absence of rainfall on Tuesday (10/14) and Wednesday (10/15). Starting on Thursday, with the organization of a new synoptic system, rains return to the South from the state of RS, with greater rainfall accumulations to the west of the state, which may exceed 100 mm.

On Friday the 17th, rainfall accumulations will be highest across the state (equal to or greater than 50 mm in 24 hours), with the development of severe thunderstorms, lightning, hail, and gusty winds. The lowest relative humidity forecast throughout the week is expected to be around 35% on Tuesday and Wednesday, October 14th and 15th. Subsequently, with the arrival of this new transient promoting moisture advection and the incursion of colder air, RH will rise again in the South on Thursday and Friday, October 16th and 17th.