The climate in Bolivia can vary drastically from one climatic zone to another. The summer months in Bolivia are November through March. The weather is typically warmer and wetter during these months. April through October, the winter months, are typically colder and drier.
     In the highlands, the weather can be very cold and temperatures frequently go below zero at night, especially on the Altiplano. Snow is common in Potosi during the winter months and sometimes also falls on La Paz and Oruro . In contrast, winter in Sucre , Cochabamba and Tarija on the Cordillera Real is a time of blue skies and comfortable temperatures. The weather in the rainforest is usually very hot and is often very wet. The drier period of the year is May to October. The section of the rainforest that borders the Cordillera Real of the Andes Mountains is a bit cooler, but still very wet. As altitude declines, the temperature rises.
     Bolivia lies in the southern hemisphere; winter runs from May to October and summer from November to April. The most important climatic factor to remember is that it's generally wet in the summer and dry in the winter. While the highlands and altiplano can be cold in the winter and wet in the summer, the only serious barrier to travel will be the odd road washout. In the tropical lowlands, however, summer can be miserable with mud, steamy heat, bugs and relentless downpours. Travel is difficult, and services may be stifled by mud and flooding. Also consider that the high tourist season falls in the winter (late June to early September), due not only to climatic factors, but also to the timing of European and North American summer holidays and the fact that it's also Bolivia's major fiesta season. This means that both overseas visitors and lots of South Americans are traveling during this period.