the big advantage of going in June is that it is not hot; as much as I love BAires but there is an air-conditioner deficiency; even places that have an a/c, these a/cs tend to be small and hardly "cool" the shops/restaurants/cafes; Summer temperatures tend to be high and the humidity can be overbearing at times;
What bothers me most about the winters is that the days are short and it gets dark early; I really like the 7-9 pm time during the summer where people are out on the streets either having their afternoon coffee or their pre-dinner drinks.