South America is a very large continent and contains 12 different countries. Generally speaking the closer to the equator the more consistent the weather is throughout the year. Whereas the further away from the equator, the more difference in the seasons. Here is some information to help you decide what is the best time to visit South America.

Brazil
Brazil is the biggest country in South America so ideal times to visit can vary. Generally speaking the warmest weather occurs from October to March. However this is also the wettest weather and so if you plan to go to Brazil to see the wildlife, some tours are not available as the access route is flooded.
During the Brazilian winter, there is less rain. The north of Brazil tends to keep a fairly consistent temperature all year, dropping only a little during July and August whereas the south of Brazil sees a larger drop in temperature starting around April or May. However, the south of Brazil still has temperatures higher than 20°c.
The best time to visit Brazil if you want good temperatures, less rain and cheaper prices is September or October. This is also the best time to go Jaguar watching.
If you are in the mood for a celebration, the Rio carnival occurs in February or early March and the streets are filled with music and colour. However due to the carnival, during this time, prices are increased.
Argentina
Argentina is a beautiful country to visit. The best time to visit Argentina is from September to November. This is Springtime in Argentina and misses the sweltering heat of November – February as well as the high prices that summer brings. September is the perfect time to go if you want to go whale watching.
Argentina holds its annual National Folklore Festival in January. This is a festival to celebrate all things Argentinean. It involves songs, dancing, bonfires and even courses and workshops to teach different aspects of their culture.
However, if you are hoping to climb the Andes, December – February is the only time you can climb the highest mountains.
If you are planning to go skiing in Argentina, July is the best time to go. July is also a good time to go if you want to see Argentina’s celebrations of independence day.
Peru
Peru is the best known as the home of Paddington Bear but if you are not a bear the best time to visit Peru is during the dry season from May to October. Although this is the cooler season, the weather is still good and there is less rain. May – October is the perfect time to hike in Peru. They have many awesome trails such as the Machu Picchu trail.
The summer in Peru is wetter but warmer. The rain can get quite heavy and if you can put up with it, summer in Peru can be cheaper and less busy. With the increase in rain, there is also an increase in greenery.
Venezuela
Venezuela has relatively consistent temperatures throughout the year, but the best time to visit Venezuela is from November to April. This is the dry season as you can enjoy warm temperatures and plenty of sunshine with less rain. This is perfect weather for hiking and sightseeing.
During the wetter season of May – October Venezuela faces more rainbows with frequent afternoon downpours. However, if you want to see some of the natural wonders of Venezuela such as their many waterfalls, this is the best time to visit as water levels are highest.
Due to the location and size of many of the countries in South America, the best time to visit can vary within a single country. you are best researching the area or county rather than the country.

On my bucket list for a long time including less-visited SA countries like Paraguay.