Brasília time +1 (UTC−02:00)
This is the standard time zone only on a few small offshore Atlantic islands. The only such island with a permanent population is Fernando de Noronha, with 2,837 inhabitants (2013 estimate), 0.0014% of Brazil's population. The other islands (Trindade, Martim Vaz, Rocas Atoll and Saint Peter and Saint Paul Archipelago) either are totally uninhabited or have small seasonally rotating Brazilian Navy garrisons or teams of scientists.
This zone is at UTC−02:00 and it does not use daylight saving time.
Brasília time, BRT (UTC−03:00)
The main time zone of Brazil corresponds to the time at the national capital city, Brasília. All the other time zones are given as offsets to it.
In addition to the Federal District (which includes Brasília), it comprises the states in the Southeast, South and Northeast Regions, plus the states of Goiás, Tocantins, Pará and Amapá. The small islands mentioned above are excepted. Almost 94% of the Brazilian population live in this time zone, which covers about 60% of the country's land area. The area comprises all six largest cities in Brazil (including Brasília).
Outside of summer time, it corresponds to UTC−03:00. During summer time, it changes to UTC−02:00, but this change is not followed by Northern and Northeastern states.
Brasília time −1 (UTC−04:00)
Outside of summer time, this time zone corresponds to UTC−04:00; during summer time, it changes to UTC−03:00, but this change is not followed by Northern states. This time zone is used in the states of Mato Grosso, Mato Grosso do Sul, Rondônia, Roraima, and most of Amazonas. Although this time zone covers about 34% of the land area of Brazil (an area larger than Argentina), little more than 5% of the country's population live there (about 11 million people, less than the city of São Paulo).
Until 2008, the areas of the state of Pará west of the Xingu River and north of the Amazon River were also part of this time zone; then they joined the rest of the state in observing Brasília time (UTC−03:00). Although other changes to Brazilian time zones enacted at that time have since been reverted (see below), Western and Northern Pará still remain in UTC−03:00.
Brasília time −2 (UTC−05:00)
This time zone was reinstated in 2013, after having been abolished for over five years. It is used in the far-western tip of the country, which includes the entire state of Acre and the southwestern portion of the state of Amazonas (west of a line connecting the cities of Tabatinga and Porto Acre, but in practice a somewhat larger area, because all municipalities that are at least partially west of that line follow this time zone in their entirety). These areas cover only about 6% of the Brazilian territory (although that is still about the size of France) and have only about 0.5% of the country's population (little more than 1 million people).
On 24 June 2008, these areas advanced their clocks by an hour, so that they became part of the UTC−04:00 time zone. However, in a non-binding referendum held on 31 October 2010, a slight majority of Acre voters voted in favour of returning the state to the UTC-05. On 30 October 2013, Brazilian President Dilma Rousseff enacted Law 12876, establishing that the time zone switch would occur on Sunday, 10 November 2013. Since then, the state of Acre and 13 municipalities in the southwestern part of the state of Amazonas are again 5 hours behind UTC.
No part of this time zone observes daylight saving time.
Unofficially, 32 municipalities in Mato Grosso and three in Goiás, located in the Araguaia valley, observe UTC−03:00 all year. Therefore, these municipalities observe the legal time in the rest of their states only during summer time (in Mato Grosso) or during standard time (in Goiás). This practice started in Barra do Garças in 1998. Banks and government services still observe the legal time in these locations.