The climate
of Brazil varies considerably mostly from tropical north (the equator traverses
the mouth of the Amazon) to temperate zones below the Tropic of Capricorn
(23°27' S latitude). Temperatures below the equator are high, averaging above
25 °C (77 °F), but not reaching the summer extremes of up to 40 °C (104 °F) in
the temperate zones. There is little seasonal variation near the equator,
although at times it can get cool enough for wearing a jacket, especially in
the rain.
At the
country's other extreme, there are frosts south of the Tropic of Capricorn and
during the winter (June–September), and in some years there are snowfalls on
the high plateau and mountainous areas of some regions. Snow falls eventually
in the mountains of the states of Rio Grande do Sul, Santa Catarina, and Paraná
and it is possible but very rare in the states of São Paulo, Rio de Janeiro,
Minas Gerais, and Espírito Santo. Temperatures in the cities of Belo Horizonte
and Brasília are moderate, usually between 15 and 30 °C (59 and 86 °F), because
of their elevation of approximately 1,000 metres (3,281 ft). Rio de Janeiro,
Recife, and Salvador on the coast have warm climates, with average temperatures
of each month ranging from 23 to 27 °C (73 to 81 °F), but enjoy constant trade
winds. The cities of São Paulo, Curitiba, Florianópolis and Porto Alegre have a
subtropical climate similar to that of southern United States, and temperatures
can fall below freezing in winter.
Precipitation
levels vary widely. Most of Brazil has moderate rainfall of between 1,000 and
1,500 mm (39 and 59 in) a year, with most of the rain falling in the summer
(between December and April) south of the Equator. The Amazon region is
notoriously humid, with rainfall generally more than 2,000 mm (79 in) per year
and reaching as high as 3,000 mm (118 in) in parts of the western Amazon and
near Belém. It is less widely known that, despite high annual precipitation,
the Amazon rain forest has a three- to five-month dry season, the timing of
which varies according to location north or south of the equator.
High and
relatively regular levels of precipitation in the Amazon contrast sharply with
the dryness of the semiarid Northeast, where rainfall is highly erratic and
there are severe droughts in cycles averaging seven years. The Northeast is the
driest part of the country. The region also constitutes the hottest part of
Brazil, where during the dry season between May and November, temperatures of
more than 38 °C (100 °F) have been recorded. However, the sertão, a region of
semidesert vegetation used primarily for low-density ranching, turns green when
there is rain. Most of the Center-West has 1,500 to 2,000 mm (59 to 79 in) of
rain per year, with a pronounced dry season in the middle of the year, while
the South and most of the East is without a distinct dry season.
Because the South Atlantic basin is generally not a
favorable environment for their development, Brazil has only rarely experienced
tropical cyclones. The country's coastal population centers are therefore not
as burdened with the need to prepare for cyclones, as are cities at similar
latitudes in the United States and Asia.