Well, I can speak about Brazil. Those three months (May, June, July) are winter in the south and rainy season in much of the northeast. Rio has nice temps and less humidity than other times of year, good for sightseeing but not great for the beach. Even in major cities, internet connections can be slower than you might expect or be used to. Brazil, and particularly a Rio, may not be the easiest to stay on a budget of any kind.