Lying entirely within tropical latitudes, Bolivia is renewed for the greatly pronounced variations of its climatic conditions. Bolivia weather is mainly tropical in the lowland parts of the country, polar in the highest parts of the Andes and semi-tropical in the northeast slopes of the Andes. Accordingly, great fluctuations are also noticeable in temperature levels, usually depending on elevation rather than seasonal variation. Rainfall patterns follow a decreasing route from north to south and most locations receive their heaviest rain during the Southern Hemisphere summer.
The northern lowland areas of Bolivia experience a tropical wet climate, characterised by heavy rainfall and high temperatures through out the year. Most parts of the northern lowlands experience daytime high temperatures of 30° C or more at any given time of the year, and significant amounts of rainfall thanks to the influence of the rain-bearing northeast trade winds that blow across the Amazon Basin. Often followed by strong winds and hail, rain in the area comes in the form of brief thunderstorms.
Bolivia weather in the country’s central lowland areas becomes tropical with a wet and a dry season. Hot, humid and rainy weather dominates the period between October and April, during which northeast trade winds become more pronounced. However, from May through September the trade winds become drier blowing in from the southeast, and as a result precipitation drops considerably becoming rather minimal. In comparison to the wet season, the clear days and cloudless nights allow for higher daily maximums and lower nightly minimums. Occasionally the region experiences a cooler spell during the winter season, when the strong winds from the east – locally known as the surazos – reach the area.
The Chaco has a semitropical, semiarid climate, with hot days and cool nights during the dry period between April and December, while between January through to March conditions become predominantly hot and humid, the northeast trade winds bringing rain in the region. Weather conditions in the mountainous areas of Bolivia considerably especially in terms of temperature and rainfall levels. Receiving up to 152 centimeters of rain annually, the Yungas is the cloudiest, most humid, and rainiest area largely because of being situated in the area where the moist northeast trade winds are pushed up by the mountains. The Cordillera Oriental, with a landscape mainly made up by sheltered valleys and basins, experiences mild temperatures and moderate rainfall amounts, averaging from 64 to 76 centimetres annually.
Areas elevated above 2,000 meters generally experience snowfall, although only those with an elevation of over 4,600 meters experience permanent snow. Areas over 5,500 meters have a polar climate, with glaciated zones, while the Cordillera Occidental is a high desert with cold, windswept peaks.
Swept by strong, cold winds, the Altiplano experiences an arid temperature that leans towards the chilly and is characterised by sharp differences in daily temperature and decreasing amounts of rainfall from north to south. Daytime temperature hovers between 15° C to 20° C on an average, although under the summer’s tropical sun they can soar as high as 27° C and even more. When nigh falls temperatures drop rapidly often slightly over freezing point as the thin air retains little heat. Lake Titicaca exerts a moderating influence, but even on its shores, frosts occur in almost every month, and snow is not uncommon.
