Finally, a notable exception to Brazil’s rainy pattern is the Northeast, particularly its interior sertão (backlands). This semi-arid region experiences an unpredictable, short, and often insufficient rainy season between February and May, derived from a different meteorological system. The rains here are a matter of survival. In a landscape of thorny scrub and dry riverbeds ( riachos ), a poor rainy season means failed crops, dying livestock, and severe drought. The famed "drought polygon" is an area where the memory of secas (droughts) has caused mass migrations and shaped a resilient, if impoverished, culture of water storage and cisterns. When rains do come, they transform the sertão almost overnight into a brief, beautiful bloom of wildflowers—an ephemeral miracle that underscores the region’s delicate dependency.
In stark contrast, the rainy season in the densely populated Southeast—home to megacities like São Paulo and Rio de Janeiro—is a more hazardous affair. Occurring during the Southern Hemisphere summer (December to March), this rainfall is driven by the South Atlantic Convergence Zone (SACZ). While these rains are crucial for recharging the region’s depleted reservoirs and supporting agriculture (especially coffee and sugarcane), their impact on urban environments is often devastating. The combination of intense, short-duration downpours on deforested hillsides and impermeable asphalt leads to catastrophic landslides and flash floods. Every summer, news reports document the grim toll: favelas clinging to steep slopes collapsing into mud, commuters trapped in waist-deep water, and infrastructure crumbling. Consequently, for urban Brazilians, the rainy season is not a gentle refreshment but a period of anxiety, traffic chaos, and a test of public works. brazil rain season
To understand the rain season, Brazil must be divided into five distinct zones: Finally, a notable exception to Brazil’s rainy pattern