IANA Time Zone vs Brazil's Legal Time Zone
A legal time zone defines the civil UTC offset used in an area. An IANA identifier is a software rule set for a representative location, including historical changes. Brazil therefore needs multiple IANA zones even though its current offsets are fixed year-round.
Brazil UTC Offsets
There is no single “Brazil UTC offset.” The official range spans UTC−05:00 through UTC−02:00. If a meeting, flight or broadcast simply says “Brazil time,” verify whether it specifically means Brasília Time.
UTC−05:00Acre and western Amazonas.
UTC−04:00Mato Grosso, Mato Grosso do Sul, Rondônia, Roraima and most of Amazonas.
UTC−03:00Federal District and most Brazilian states, including São Paulo and Rio de Janeiro.
UTC−02:00Eastern Atlantic island zone, including Fernando de Noronha.