Brazil's climatic regions           

1) The Amazon Basin -- far North
This is the largest area in the world with a typical equatorial climate. Rainfall throughout, is above 1,500 mm/60 in a year and in much of the region over 2,000 mm//80 in. There is no real dry season but there are some variations in the period of the year when most rain falls. Belém at the mouth of the Amazon is the wettest place and the heaviest rainfall comes in the months January to May, but all months have many days with rain.

2) The Brazilian Plateau
This region is as large and extensive as the Amazon basin but, lying farther south and being at a moderate altitude, it has a very different climate. There is a much more distinct wet and dry season, and both the daily and annual temperature ranges are quite marked.

3) The East Coast within the Tropics
This long, narrow region extends from south of the mouth of the Amazon to Santos, and has a typically hot, tropical climate. There are, however, some important differences in the season of greatest rainfall from north to south. South of Bahía, near Sao Paulo, the distribution of rainfall changes and the table for Rio de Janeiro shows that the wettest period is from November to April. Here some appreciable rainfall occurs in all months. Nowhere on this coast do maximum temperatures rise so high as to be uncomfortable, though the combination of warmth and humidity can be uncomfortable at night. Daytime heat is often tempered by the sea breeze.

Along this coast, from Recife southwards (including Salvador), cloudy and cool weather with some rain or drizzle may last for a few days at the period of low sun. Temperatures never drop very low and frost is unknown on the coast but in the hills, behind Santos, occasional frosts may damage the valuable coffee crop.

4) The Southern States of Brazil outside the Tropics -- far South
This region consists of the southern states of Paraná, Santa Catarina, and Rio Grande do Sul. Both along the coast and in the plateau districts inland, the climate is warm-temperate rather than tropical, and is similar to that found in Uruguay and northern Argentina.

As the table for Porto Alegre shows, even on the coast there is a distinct cooler season when frost can be expected in the winter months. Here winter has a real significance and the difference between the seasons is determined by temperature rather than rainfall.

BBC Weather is the source for the weather information and graphs.