Sun's position on summer solstice
The Sun at solar noon (meaning that it is on the meridian) will be in one of these directions:


Due south if the declination of the Sun is less that your latitude. (For Brasilia, that occurs from Nov 6 to Feb 5, approximately)
Directly overhead (at the zenith) if the declination of the Sun is the same as your latitude. (For Brasilia, that occurs Nov 5 and Feb 6, approximately)
Due north if the declination of the Sun is more than your latitude. (For Brasilia, that occurs from Feb 7 to Nov 4, approximately)