September is expected to bring rain and above-average temperatures to Brazil.

For the month of September 2026, the climate forecast from the National Institute of Meteorology (Inmet) indicates a predominance of rainfall above the historical average in areas of the Central-West, Southeast, and South of Brazil, and part of the North region. On the other hand, below-average volumes are expected in sectors of the Northeast and part of the North.

Na Northern RegionAreas with below-average rainfall totals predominate, especially in large parts of Roraima, Amazonas, and Pará. In addition, rainfall totals near or above average are expected in Rondônia, western Acre, central and northern Amapá, as well as specific areas in northern and southwestern Amazonas and northwestern Pará.

About North East RegionRainfall volumes are expected to remain mostly within the normal range for September. Above-average rainfall is forecast only in southern Piauí, southwestern Maranhão, and western and southeastern Bahia. On the other hand, the eastern part of the region – encompassing central-eastern Rio Grande do Norte and Paraíba, northeastern Bahia, and the states of Sergipe and Alagoas – is expected to experience below-normal precipitation.

For Midwest regionThe forecast indicates accumulated rainfall within the historical average. The forecast for above-average rainfall is concentrated in north-central and southeastern Mato Grosso, southern, southwestern, and southeastern Goiás, and in a large part of the state of Mato Grosso do Sul (with the exception of the eastern part of the state, which should remain within the climatological average).

For SoutheastThe forecast indicates that accumulated rainfall will be predominantly above the historical average across virtually the entire region. The only exception is the far north of Minas Gerais, which may experience volumes within the climatological average.

About SouthThe trend is for above-average rainfall in most of Rio Grande do Sul. In the western, southwestern, and northeastern parts of the state, as well as eastern Santa Catarina, the forecast is for rainfall accumulations close to the average.

Temperatures will remain above average.

The forecast for September indicates that temperatures should be above average in much of the country, with the largest deviations expected in the North, Northeast, and Central-West regions of Brazil.

Na Northern RegionThe forecast predicts predominantly above-average temperatures across much of the region, with positive deviations of approximately 1,0°C to 2,0°C. In northwestern and eastern Amazonas and southern Roraima, temperatures are expected to be about 1°C above the average. In other areas, deviations of up to 1,5°C are predicted. It is noteworthy that central and southeastern Pará and the far west of Tocantins may register temperatures up to 2,0°C above the average.

Na North East RegionThe forecast indicates temperatures up to 1,5°C above the climatological average in much of Matopiba and the central region of Bahia. In other areas of the region, temperatures are expected to remain up to 1°C above the climatological average for the month.

Na Midwest regionThe forecast indicates average temperatures up to 1,5 °C above the climatological average for the month across the central-eastern strip of Mato Grosso and in much of Goiás. In other areas of the region, deviations of up to 1,0 °C are expected in relation to the climatological average for September.

Na SoutheastThe forecast predicts above-average temperatures across much of the region, especially in the states of Minas Gerais, Espírito Santo, and a large part of Rio de Janeiro, with deviations of up to 1,5 °C. In the São Paulo region, the eastern part of the state is expected to experience deviations of up to 1,0 °C, while the remaining regions of the state should have temperatures within the climatological average.

Na SouthThe forecast indicates average temperatures across most of the region. The largest positive deviations are expected in eastern Paraná, with values ​​up to 0,6 °C above the climatological average. 

Possible impacts on agricultural crops

In much of the Northern RegionThe forecast of below-average rainfall, coupled with higher temperatures, is expected to intensify the evaporative demand of the atmosphere, especially over crops that are going through the most sensitive period of their phenological cycle. This scenario tends to reduce soil water availability, especially in crops grown under rainfed systems, increasing the risk of water deficit during critical development phases. 

For third-crop corn fields in Roraima, predominantly in the grain-filling stage, water restriction could accelerate the plant cycle, shorten the grain filling period, reduce the final weight of the grains, and increase the unevenness of the seed lots, compromising the productive potential of the later-sown areas. On the other hand, in areas where third-crop corn is already in the maturation or harvesting phase, the predominance of dry weather tends to favor uniformity of maturation, natural drying of the grains, and the progress of field operations. This same scenario could benefit the completion of the soybean harvest in the state, reducing the risk of losses due to excess moisture and optimizing the operational performance of agricultural machinery.

Na North East RegionThe weather forecast indicates rainfall close to the climatological average in much of the region, with above-average accumulations in southern Piauí, southwestern Maranhão, and western and southeastern Bahia. On the other hand, below-average volumes are expected in the eastern part of the region, associated with above-average air temperatures throughout the Northeast.

The combination of below-average rainfall and higher temperatures could intensify water scarcity affecting third-crop corn fields in the Agreste and Sertão regions of Pernambuco, eastern Alagoas, and northeastern Bahia. In rainfed fields still in the grain-filling stage, these conditions may shorten the grain filling period, limit dry matter accumulation, increase the incidence of shriveled grains, and promote uneven ripening, negatively impacting yield potential. Conversely, in areas where crops have reached maturity or are being harvested, the predominance of dry weather tends to favor uniform ripening, natural grain drying, and the progress of field operations.

Still in the Agreste region of Pernambuco, the sowing and emergence of the first bean crop is expected to occur under conditions of below-average rainfall and above-average temperatures. This scenario could compromise germination and seedling emergence, favoring the formation of uneven stands, increasing the risk of replanting, and delaying the effective establishment of the crop and the sowing window.

The forecast of below-average rainfall and higher temperatures in the eastern and semi-arid northeastern regions of Brazil could increase the demand for irrigation in the fruit-growing areas of the São Francisco and Jaguaribe river valleys. These conditions also tend to restrict pasture growth, reduce forage availability, and increase pressure on water resources destined for extensive livestock farming. 

Na Midwest regionThe weather forecast for September indicates rainfall close to the climatological average in most of the region, with above-average volumes in north-central and southeastern Mato Grosso, southern, southwestern and southeastern Goiás, and much of Mato Grosso do Sul. Air temperatures are expected to remain above average in most of the region.

In this scenario, harvesting operations, which account for a large part of agricultural activities in September, are expected to take place under predominantly favorable conditions, although more restricted operational windows may be observed in areas with above-average rainfall forecasts.

In these areas, the increased frequency of rainfall events could delay the completion of the cotton, sorghum, and second-crop corn harvests in Mato Grosso do Sul, and the third-crop bean harvest in Goiás. Besides hindering the movement of machinery and equipment, the increased grain moisture could raise the costs of artificial drying and increase the risk of quality losses. In cotton, rainfall over areas with open bolls could favor fiber staining and increase the impurity content. In beans, rainfall during maturation and harvesting could favor darkening of the seed coat, reducing the commercial value of the production.

For pastures, conditions should be more favorable in areas of southern Mato Grosso do Sul, where increased soil water availability may stimulate the resumption of forage growth. In other areas of the region, however, the combination of more limited rainfall and high temperatures may restrict biomass production, reducing forage availability and increasing the need for supplemental feed for livestock. 

Na SoutheastForecasts indicate above-average rainfall across much of the region, accompanied by above-normal temperatures, particularly in Minas Gerais. This scenario tends to increase the evaporative demand of the atmosphere and, consequently, the water needs of plants during this period.

Second-crop cultures, such as corn and cotton, are predominantly in the maturation and harvesting phases. In this context, the occurrence of higher temperatures, associated with dry periods, should provide favorable conditions for the completion of the harvest and the execution of harvesting operations. Late-sown bean areas, on the other hand, still require water availability to complete their cycle. Thus, irrigation tends to continue to be used, especially in northwestern Minas Gerais, due to the high water demand associated with the crop development phase and higher temperatures.

Wheat crops in Minas Gerais and São Paulo should also benefit from the predicted conditions, especially for grain maturation and harvesting. In São Paulo, the forecast of above-average rainfall, combined with temperatures close to the climatological average, should favor the maintenance of suitable conditions for the start of soybean sowing. Furthermore, the expectation of soil water storage exceeding 70% of the available water capacity in much of the state represents a favorable condition for germination, emergence, and proper plant stand establishment.

For coffee farming, the forecast of above-average rainfall in the main producing regions of the Southeast could favor the replenishment of soil moisture and stimulate the opening of flower buds after the physiological rest period. If rainfall is well distributed, this scenario tends to contribute to a more uniform flowering and initial fruit set. However, isolated rains, interspersed with new dry periods, could cause successive flowerings and increase the unevenness of the next harvest. In Minas Gerais and Espírito Santo, above-average temperatures could also increase the water demand of the plants and compromise fruit set if dry spells occur after flowering. In areas with late harvesting, the higher frequency of rainfall could restrict field operations and hinder grain drying, increasing the risk of quality loss.

For citrus farming, especially in the producing belt of São Paulo, the Triângulo Mineiro region, and southwestern Minas Gerais, the forecast of above-average rainfall tends to favor the recovery of soil moisture, the development of shoots, and the occurrence of the main flowering. In much of the interior of São Paulo, temperatures close to average may provide favorable conditions for flowering and initial fruit set. In the Minas Gerais sector of the belt, however, higher temperatures may increase water demand and hinder fruit set if dry periods occur after flowering. Frequent or intense rainfall during flowering may also favor the occurrence of floral rot and reduce the effectiveness of phytosanitary treatments. In harvested areas, the increased frequency of rainfall may temporarily restrict field operations and hinder access to orchards. 

Na SouthThe forecast indicates above-average rainfall and temperatures close to the climatological average across much of the region. This scenario tends to reduce the occurrence of widespread and late frosts, which can have significant impacts on winter crops, especially when they occur during the flowering and grain-filling stages, compromising quality and productivity. In Paraná, rainfall may increase the risk of excess moisture during the grain-filling and harvesting stages of winter crops. These conditions may also hinder adequate soil preparation and, consequently, restrict operations for the start of the soybean crop season in the state.

In much of Rio Grande do Sul and Santa Catarina, the combination of temperatures and high humidity may favor the occurrence and spread of fungal diseases in crops such as wheat and oats, increasing the need for phytosanitary monitoring and the adoption of appropriate management measures. These conditions are particularly favorable to the development of Fusarium head blight, one of the main diseases affecting wheat, which can cause significant reductions in grain quality and productivity, especially when it occurs during flowering and the beginning of grain filling.

The predicted temperature and rainfall conditions should favor pasture development. In this context, attention to animal management in the paddocks is recommended, avoiding excessive concentration and trampling, which can damage plants and compromise forage recovery and availability.