The chapter begins with a brief overview of the observations, datasets, and methodologies commonly employed in global and regional climate studies. It then summarizes the fundamental aspects of the global climate that are essential for understanding regional climate dynamics, such as the planetary energy balance, the three-dimensional structure of the general atmospheric circulation (including the Hadley and Walker cells as well as the jet streams), and the key processes underlying monsoon systems. These notions are applied to describe the main climatic features of South America and to introduce the South American monsoon system. Although awareness that a summer monsoon existed in South America emerged in the late 1990s, the concept remains relatively unfamiliar to scientific and technical communities focused on regional climate impacts but lacking expertise in climate dynamics. Given that the La Plata Basin extends into midlatitudes, the chapter also discusses the role of mesoscale (subdaily) and synoptic-scale (few days) disturbances in shaping the region’s climate, with particular emphasis on the influence of the Andes Mountains in modulating these disturbances.