Rosario, Argentina's third-largest city, sits on the western bank of the Paraná River in the humid Pampas of east-central Argentina, on a low plain about 300 km northwest of Buenos Aires, at approximately 32.96°S, 60.69°W. It has a humid subtropical climate (Köppen Cfa) — hot, humid summers and mild winters — with rain spread through the year but concentrated in the warm season, and no true dry season. Being in the Southern Hemisphere, its seasons are reversed relative to the Northern.

Summer, from December to February, is hot and humid, with January the warmest month — average highs around 31°C and warm, sticky nights — and hot spells that can climb into the high 30s. Its inland-but-humid setting makes the heat feel heavy, and afternoon and evening thunderstorms are frequent, sometimes severe, bringing heavy downpours, and the pampero wind can sweep in with sudden storms and a drop in temperature.

Winter, from June to August, is mild, with July the coolest month — average highs around 17–18°C and cool nights near 6–8°C, occasionally dropping to frost on clear nights. Days are often mild and pleasant, interspersed with grey, damp spells and cold fronts, and genuine cold is brief. Rain is lighter than in summer but not absent.

Rosario is fairly wet, receiving on the order of 1,000–1,080 mm of rain a year, spread through the year with no dry season but with a clear warm-season maximum from spring to autumn, when thunderstorms are most frequent; winter is the drier season. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

Rosario's weather is typical of the humid Pampas, shaped by the clash of contrasting air masses: warm, humid tropical air from the north brings sultry, stormy spells, while the cool, dry pampero sweeping up from the south can end a hot spell abruptly with thunderstorms and fresher air. Its riverside setting on the Paraná keeps humidity high through the warm season.

To follow any single measurement in Rosario more closely, use our live instruments: the online barometer for atmospheric pressure, the thermometer for temperature, the hygrometer for humidity, the anemometer for wind speed, the wind vane for wind direction, and the rain gauge for rainfall.