Santa Cruz de la Sierra, Bolivia's largest city, sits in the eastern lowlands of the country, on the hot, flat plains at the edge of the Amazon and Gran Chaco basins at around 400 metres above sea level, at approximately 17.78°S, 63.18°W. Far from the high Andes, it has a tropical savanna climate (Köppen Aw) — hot and humid for most of the year — with a wet summer and a drier winter, punctuated by sudden cold winds sweeping up from the south.

Summer, from November to March, is hot, humid and the rainy season, with highs around 30–32°C and warm, sticky nights, occasionally climbing higher in humid heat. This is when most of the year's rain falls, in heavy afternoon and evening thunderstorms, and the combination of heat and humidity can feel oppressive on the lowland plain. Being in the Southern Hemisphere, its seasons are reversed relative to the Northern.

Winter, from June to August, is warm and drier, with highs still around 26–28°C and milder, more comfortable conditions overall. Its most distinctive feature is the surazo — a sudden cold wind sweeping up from Patagonia and the Argentine pampas — which can abruptly drop the temperature by 15–20°C for a day or two, bringing grey, chilly, damp weather that contrasts sharply with the surrounding tropical warmth.

Santa Cruz is fairly wet, receiving on the order of 1,300–1,400 mm of rain a year, concentrated in the summer wet season from November to March, when heavy thunderstorms can cause flooding on the flat terrain; the winter from June to August is drier. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

Santa Cruz's most distinctive weather event is the surazo, the cold southerly wind that periodically surges up from the far south to interrupt the tropical warmth with sudden, sharp cold snaps, most often in winter. Otherwise its lowland position gives it a hot, humid, thundery tropical climate quite unlike the cold Andean highlands to the west, with the wet summer bringing the heaviest rain and the risk of flooding.

To follow any single measurement in Santa Cruz 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.