Brazilian summer time (horario de verão in Portuguese) comes to an end at midnight between Saturday 16 and Sunday 17.
This change applies to the South, Southeast and Centre-West regions of the country (the states affected by the change are: Rio Grande do Sul, Santa Catarina, Paraná, São Paulo, Rio de Janeiro, Espírito Santo, Minas Gerais, Goiás, Mato Grosso and Mato Grosso do Sul, as well as the Distrito Federal). Clocks will have to be put back one hour.
Bahia, in the Northeast, did not implement daylight saving time this year – reversing a trend from the past when it became the only state in the Northeast region to do so.
The easiest way to find out what time it is on any Brazilian state at a given time is to use the tool I explained at What time is it in Brazil?