| Driver | Type | Primary Affected Region | Seasonal Influence | |--------|------|------------------------|--------------------| | (South Atlantic Convergence Zone) | Convective band | Southeast, Center-West | Summer (Dec–Feb) | | ITCZ (Intertropical Convergence Zone) | Zonal convergence | North (Amazon, Northeast coast) | Mar–May & Oct–Nov | | MCCs (Mesoscale Convective Complexes) | Thunderstorm clusters | South, parts of Southeast | Spring & Summer | | ENSO (El Niño Southern Oscillation) | Teleconnection | Nationwide | Year-round (interannual) | | South American Monsoon System | Monsoonal circulation | Amazon to Southeast | Oct–Mar |

, making it one of the most water-abundant nations on earth. However, this national metric obscures extreme regional variations. Annual totals swing dramatically from over 3,000 mm (118 inches) in the dense northern rain forests to under 600 mm (23.6 inches) in the arid northeastern interior.