If you are planning to visit South America, do keep in mind that the seasons there are the reverse of those in North America. The spring season is from September to December, summer is from December to March, fall is from March to June and winter is from June to September. In general, the seasons there are the same as those in Australia although South America has its own distinct weather and climate.
Since South America is so vast, the best time to travel there actually depends on your specific destination and what you want to do. Just remember some important climatic conditions such as in the Altiplano region where it rains between December and March when it is supposedly summer. Rio de Janeiro has its rainy season normally beginning from the end of February to March. At the area above the Tropic of Capricorn, the weather is hot while it’s humid in the coastal areas of Ecuador, Colombia, Venezuela and the Amazon jungle. In the southern part of Puerto Montt around the area of Tierra del Fuego, the best time to visit is from September to April.
Brazil can be visited all year round. However, not all parts of Brazil are best for travel because summer there can be very humid plus it’s pouring during that time. So the best time for traveling is usually July and August (remember that their seasons are reverse from the Northern Hemisphere).
Lima, Peru is best visited during summer when it is dry (December -February). If you’re eyeing the coastal areas, it’s recommended to go there between the late winter to late spring season.
Chile as well as Buenos Aires in Argentina are best visited during the spring season or autumn.
As for Mexico, the ideal time to visit is between the months of October and May. Temperatures at this time are very comfortable and humidity is less.