Time zone · Americas
AST
Amazon Standard Time
Amazon Standard Time (AST) covers key cities deep in Brazil's Amazon region and neighboring states, all set at a steady UTC-4 with no daylight saving shifts—so what you see is what you get, year-round.
Friday, June 5, 2026
Current offset
UTC-04:00
Standard · -04
Daylight saving
Not observed
Year-round standard time
IANA zones
5
None observe daylight saving
DST offset
—
No summer variant
About AST
A fixed, year-round offset.
Amazon Standard Time (AST) covers key cities deep in Brazil's Amazon region and neighboring states, all set at a steady UTC-4 with no daylight saving shifts—so what you see is what you get, year-round.
IANA zones · the technical identifiers
The 5 zones that resolve to AST.
For software, always store the IANA identifier — never the abbreviation alone. The database keeps these zones distinct because their rules can, and historically did, diverge.
Cities currently on AST
The same hour, city by city.
4 cities · all UTC-04:00
Where AST is used
One country.
Same offset · UTC-04:00
Other zones at UTC-04:00 right now.
These named zones share AST's offset today. When daylight saving rules differ, they drift apart for part of the year.
Frequently asked questions
Common questions about AST, daylight saving, and how to handle it in software. Can't find what you need? Email [email protected].
- Why don't these Amazon-region zones use daylight saving time?
- Since they sit close to the equator, cities like Manaus and Boa Vista don’t experience big seasonal swings in daylight, so there’s little practical benefit to shifting clocks forward or back.
- Is Amazon Standard Time the same as Atlantic Standard Time?
- They share the same UTC-4 offset, but Atlantic Standard Time is used in Canada’s Atlantic provinces and the Caribbean, while Amazon Standard Time is specific to parts of Brazil.
- What are the main cities in Amazon Standard Time?
- Representative cities include Manaus, Boa Vista, Porto Velho, Cuiaba, and Campo Grande, spread across several northern and central-western states of Brazil.
- Does any DST ever used in these zones?
- Some of Brazil’s Amazon regions briefly experimented with daylight saving earlier in the 2000s, but they were excluded from national DST rules after 2008 and haven’t observed it in recent years.
- How does AST offset affect scheduling with São Paulo or Rio?
- Amazon Standard Time is usually two hours behind São Paulo (UTC-3), so a noon meeting in AST corresponds to 2 p.m. in eastern Brazil, but this can shift if São Paulo is observing daylight saving.
- What states in Brazil currently follow AST?
- AST is used in the state of Amazonas and Roraima, plus parts of Mato Grosso, Mato Grosso do Sul, Rondônia, and Pará in northern and central-western Brazil.
- Is Amazon Time the same across the entire Amazon region?
- No—parts of Amazonas and other western areas of Brazil use UTC-5 or sometimes UTC-4 year-round, so specific cities like Manaus follow AST while others do not.
- How does constant UTC-4 affect daily life in AST?
- With no clock changes, people in Amazon Standard Time can plan schedules consistently, making business, school, and transport timetables more predictable throughout the year.
- How does AST relate to international time zones during coordination?
- Because AST never shifts for DST, global teams can use it as a stable reference—AST is always UTC-4, simplifying calendar invites and recurring calls with these Brazilian regions.
Free · Developer API
Time, as JSON.
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