Brazil is slightly smaller than the United States. As it is one of the few South American countries not to include the Andes mountains, there are no permanent snowfields in Brazil. The country is split into four distinct climatic regions: the Amazon Basin, the Brazilian plateau, the coastlands within the tropics and the southern states.
The Amazon Basin is the largest area in the world with a typical equatorial climate. Rainfall in some places can exceed 2,000 mm (80") and there is no real dry season. Tropical temperatures (27-32 °C/81-90 °F) are typical. Frost is unknown, but in the south of the region, occasional cold spells (friagem) cause night temperatures to fall below 10 °C (50 °F) making it most uncomfortable for the people. Daytime temperatures of 38 °C (100 °F) are rare, but the high humidity and monotony of the temperatures can make conditions very unpleasant.
The Brazilian Plateau is another very large region, but being south of the Amazon Basin and at a moderate altitude, it has a very different climate. There is a very distinct wet season at the time of high sun, with almost all the rainfall (about 1,500 mm/60") falling between October and April. The dry northeast of the region has a much lower average rainfall (in some places less than 750 mm/30"), but it is also very irregular from year to year, causing prolonged droughts. The tropical east coast (including Rio de Janeiro) has a typically hot tropical climate, although there are significant differences in the season of greatest rainfall from north to south.
Near the Amazon mouth all months are wet, but the greatest rainfalls occur from December to May (in excess of 300 mm/12" per month). Further south (e.g. Recife) the wettest months are May to August, although amounts tend to be lower. Further south still (at Rio) the wettest period is November to April. Nowhere on this coast do maximum temperatures rise so high as to be uncomfortable, but the combination of warmth and high humidity can be unpleasant at night. Daytime heat is often tempered by sea breezes, but temperatures never drop very low. Frost is unknown on the coast, but in the hills occasional frosts may damage the coffee crop.
The southern states have a warm temperate climate, although on the coast a distinct cooler season can produce frosts. Winter has a real significance in this region, and the difference between the seasons is determined by temperature rather than rainfall. The area is often affected by invasions of cold air from the Antarctic, but during summer, temperatures can rise to levels similar to the tropical regions. The region has a healthy and pleasant climate with an average of 8-9 hours of sunshine a day in summer. On the higher land, frosts are common, but snow is very rare. Inland the wettest months are during the summer in contrast to the coast.