Remember that the southern hemisphere seasons are reversed - with summer roughly November to February, and winter in June to August.
Peru is pretty much a year round destination thanks to its proximity to the equator. However, visit between January and March and you’ll be slap bang in the middle of the rainy season. The Inca Trail closes for maintenance throughout February.
Northern Argentina and Chile along with southern Brazil experiencing summer temperatures all the way from November through to March and April where coastal towns and beaches tend to attract the crowds.
At this time, Patagonia is at its warmest and most accessible - particularly in the far south, which gets cut off during the harsh winters. Many place here will shut up shop from June until September.
South America is well known for Easter celebrations so bear this in mind if you’re planning on traveling or finding somewhere to stay without booking in advance.
July and August, are often peak times for travelers wanting to undertake the Inca Trail or visit the Galapagos Island and if you’re planning on searching for Machu Pichu or wildlife watching then make sure you book six months in advance. Permits are issued around February every year - but it's never to soon to be put on the list.
October and November are often thought of as the best times to visit South America as several countries experience springlike conditions with numerous wild flowers and newborn animals appearing with the rise in temperatures.
December finds popular coastal areas getting busier, whilst natural regions, such as the Pantanal and the Amazon, get the worst of the wet weather. Read up on the region you're planning to visit to find out if it can be accessed during this time; some areas are cut off, while others can be toured by boat - a magical rainforest experience.