Brazil is the fifth largest country in the world and as a result has a series of microclimates across the country.
It can be visited at any time of year, but most travellers visit in the summer months from December to February, when it is hottest on the coast and in Rio de Janeiro.
Carnival takes place across the country, but is most impressive in Rio. It begins on the Friday preceding Lent and ends on Ash Wednesday. If planning to travel over Carnival, plan well ahead as hotels do get booked up and will often ask guests to stay for a minimum number of nights (normally the duration of Carnival).
The Pantanal wetlands can be visited year round, but the most popular time to go is during the dry season from May to October. The wet season can be very hot and humid, but has the advantage of being a particularly good time to see birdlife.
The Amazon is hot and humid all year, but the wettest months are March to May. Broadly speaking it follows a similar weather pattern to the Pantanal, which makes June to September a popular time to visit.
Iguassu Falls can also be visited year round, but temperatures do drop in the winter months of June to August.
If visiting the north-east of the country and the Lençois Maranhenses National Park, the best time to go is from June to September, which is after the rainy season and when fresh water pools form between the sand dunes.