Most countries are hot year round, but if you are at an altitude of anything above 2000 metres, it will start to feel cool, irrelevant of the season. Above 3000 metres and you’ll feel cold, above 4000 metres and it starts to get freezing.

This is the most important consideration in terms of what clothes to pack - the altitude of the places you will visit. In South America, the “winter months” of May to September only really affect Argentina, Chile and Southern Brazil - all of these places become progressively cooler the further one travels South.