Cloud winds obtained from SMS-I geostationary satellite images for the Southern Hemisphere summer-time are used to describe the tropospheric circulation over tropical and subtropical South America. These data provide good spatial and temporal, coverage over South America for at least two levels in the troposphere. The summertime circulation derived from cloud winds is similar in pattern to that obtained from sparse conventional winds but is more intense. The, major features of the time-averaged circulation at the upper level (300–100 mb) are an intense, quasi-stationary anticyclone-trough system extending over most of South America north of 35°S; a band of easterly flow near 10°S; and strong cross-equatorial northward flow between 60 and 80°W longitudes. At the lower level (900–700 mb) the major features are the northerly and northwesterly jet-type flow along the eastern slopes of the central Andes and northeasterly trades over much of the remainder of the continental region to the north and cast... Abstract Cloud winds obtained from SMS-I geostationary satellite images for the Southern Hemisphere summer-time are used to describe the tropospheric circulation over tropical and subtropical South America. These data provide good spatial and temporal, coverage over South America for at least two levels in the troposphere. The summertime circulation derived from cloud winds is similar in pattern to that obtained from sparse conventional winds but is more intense. The, major features of the time-averaged circulation at the upper level (300–100 mb) are an intense, quasi-stationary anticyclone-trough system extending over most of South America north of 35°S; a band of easterly flow near 10°S; and strong cross-equatorial northward flow between 60 and 80°W longitudes. At the lower level (900–700 mb) the major features are the northerly and northwesterly jet-type flow along the eastern slopes of the central Andes and northeasterly trades over much of the remainder of the continental region to the north and cast...