The climate of Bolivia varies drastically from one ecoregion to the other, from the tropics in the eastern llanos to polar climates in the western Andes. The summers are warm, humid in the east and dry in the west, with rains that often modify temperatures, humidity, winds, atmospheric pressure and evaporation, giving place to very different climates. When the climatological phenomenon known as El Niño takes place, it provokes great alterations in the weather. Winters are very cold in the west, and it snows around the mountain ranges, while in the western regions, windy days are more usual. The autumn is dry in the non-tropical regions.
• Llanos. A humid tropical climate with an average temperature of 30°C. The wind coming from the Amazon rainforest causes significant rainfall. Starting in May, there is low precipitation because of dry winds, and most days have clear skies. Even so, winds from the south, called surazos, can bring cooler temperatures lasting several days.
• Altiplano. Desert-Polar climates, with strong and cold winds. The average temperature ranges from 15 to 20°C. At night, temperatures descend drastically to slightly above 0°C, while during the day, the weather is dry and solar radiation is high. Ground frosts occur every month, and snow is frequent.
• Valleys and Yungas. Temperate climate. The humid northeastern winds are pushed to the mountains, making this region very humid and rainy. Temperatures are cooler at higher elevations. Snow occurs at altitudes of 2000 meters.
• Chaco. Subtropical Semi-arid climate. Rain and humidity in January and the rest of the year, with warm days and cool nights
