South of the Equator, summer is characterized by convective thunderstorm activity. The Amazon Basin experiences high humidity and frequent afternoon rainfall, while southeastern South America—including northern Argentina, Uruguay, and southern Brazil—suffers occasional heatwaves (temperatures >40°C) and severe storms with hail and tornadoes. The Atacama Desert remains rainless due to persistent coastal subsidence.
The Southern Ocean is warming and freshening due to increased glacial melt from Antarctica. This alters thermohaline circulation and reduces summer sea ice extent around Antarctica, with profound implications for albedo feedback and marine ecosystems. summer southern hemisphere
Climate models project a poleward expansion of subtropical dry zones, leading to reduced winter-spring rainfall in southern Australia, western South Africa, and central Chile—but summer rainfall may decrease or become more variable. Conversely, tropical regions (e.g., northern Brazil, Madagascar) may see intensified summer rainfall and flooding. South of the Equator, summer is characterized by
The AAO, or Southern Annular Mode (SAM), describes the north-south movement of the westerly wind belt. During a positive SAM phase in summer, westerlies contract poleward, reducing rainfall over southern Australia and southern South America but increasing it over Antarctica’s periphery. A negative SAM phase allows cold fronts to penetrate farther north, bringing unseasonably cool or wet conditions to mid-latitudes. The Southern Ocean is warming and freshening due