The El Niño climate phenomenon will influence the Brazilian winter starting Sunday, June 21, 2026 [1].
This atmospheric shift is significant because it alters precipitation and temperature patterns across the country, affecting agriculture and public safety in multiple regions.
The winter period is scheduled to last from June 21 until Sept. 22, 2026 [2]. According to reports, El Niño alters atmospheric circulation by intensifying humid air masses, which increases rainfall in the South and parts of the Southeast [3]. While some forecasts suggest precipitation will remain near historical averages, other data indicates rainfall will be above the historical average for these regions [1, 4].
Temperature variations are expected to be widespread. In the Alto Tietê region of São Paulo, temperatures are projected to remain above the historical average [5]. Conversely, a polar wave marking the start of the season could cause temperatures to drop to 0°C in the South and Southeast [6].
The phenomenon typically creates a divide in moisture distribution across the continent. While the South and Southeast face increased humidity, the North and Northeast regions are expected to experience drier conditions [3].
In the Serra Catarinense, residents should prepare for a mix of increased rainfall, and the risk of intense cold [3]. These fluctuations are a direct result of how El Niño modifies the movement of air masses over the South American landmass [3].
“El Niño alters atmospheric circulation by intensifying humid air masses.”
The presence of El Niño during the 2026 winter creates a volatile meteorological environment for Brazil. By shifting moisture away from the North and Northeast toward the South and Southeast, the phenomenon increases the risk of flooding in southern basins while potentially exacerbating droughts in the north. The simultaneous possibility of above-average warmth in some areas and freezing temperatures in others suggests a season of extreme instability.
