Average Annual Temperatures
Despite the fact that 90 percent of Brazil lies within the tropical zone, the vast majority of its habitants – more tthan 60 percent – live in areas where temperatures are moderated by altitude, sea winds, or cold polar fronts.
Brazil weather can be divided in five distinct climatic regions: equatorial, tropical, semi arid, highland tropical, and subtropical. Weather in cities situated at the plateau – for example São Paulo, Brasília, and Belo Horizonte – is of the mild variety, temperatures averaging 66°F (19°C) while the largely warm weather of coastal cities like Rio de Janeiro, Recife, and Salvador is balanced by the influence it receives by the constancy of the Trade Winds. Weather becomes subtropical and very similar to that usually associated with parts of the U.S. and Europe in the southern Brazilian cities of Porto Alegre and Curitiba, with frost making frequent appearances. During the winter season, temperatures in the area remain cold, occasionally dropping bellow freezing point.
On the other hand, the Amazon region is infamous for suffering from blistering heat, a reputation with little basis on actuality, as temperatures of more than 90°F (32°C) are rarely experienced there, its annual average temperature being in the range of 72 79°F (22-26°C), and very small and rather insignificant seasonal variation between the warmest and the coldest months. Brazil’s hottest part is its northeast area, with frequent occurrences of temperatures of more than 100°F (38°C) during the dry season, between May and November. However, in comparison to the Amazon region, the northeast has greater seasonal variation in temperatures
From Recife to Rio de Janeiro and along the Atlantic region mean temperatures range from 73°F to 81°F (23 27°C), dipping considerably in the inland or higher ground areas, ranging from 64°F to 70°F (18 21°C). The seasons become more pronounced and the annual range of temperature is greater in the areas south of Rio, with average temperature in the range between 63°F to 66°F (17 19°C).
Average Annual Rainfall
Around the mouth of the Amazon River near the city of Belém rainfall is the most intense in Brazil and the same applies to vast upper regions of Amazônia, both areas receiving more than 78 inches (2,000 millimeters) of rain falls every year. The area along the edge of the great escarpment in the state of São Paulo is also of immense importance to Brazil’s precipitation patterns, while most of Brazil has moderate rainfall of between 39 to 59 inches (1,000 to 1,500 millimeters) a year. As a general rule the country receives its bulk of rainfalls during summer, between December and April.
Winter in Brazil tends to be a time of dryness. Encompassing 10% of the country’s territory the northeast region is by far Brazil’s driest part, therefore deservedly receiving the moniker "polygon of drought". Rainfall in this region is undependable and the evaporation rate is very high, making conditions for raising crops extremely difficult and unfavourable.
Along the coastline, south from Recife, the trade winds triggers rainfall in the mountains, although parts of the area, such as the region south of Salvador, the hinterland is dry because the rain is dumped on the mountains leaving very little for the area behind.
