I have never been to South America....or the southern hemisphere for that matter...but could imagine it would be warm! The beginning of winter would mean the beginning of summer there. I saw the .nl in your post and assume you are from Holland. My best guess would be that the weather in South America would be one hundred times better than the weather we have in northern Europe in November. At least you would get to see the sun and could leave the rain coat, umbrella and rubber boots at home!
you will be in more than one climate. BA and Valparaiso (close to Santiago which is where you'll fly into) will be warm, but as you go around Cape Horn you will have some very chilly weather. This is the last major land mass before Antarctica. I am dying to go to South America (other than Friday's flight to Brazil) but I think I want to go to Antarctica even more.