Time zone · Americas
AST
Acre Standard Time
Acre Standard Time (AST) is a fixed clock — there are no daylight‑saving surprises, no twice‑yearly jumps; Brazil’s state of Acre and the far west of Amazonas stay at UTC‑05:00 all year.
Wednesday, October 14, 2026
Current offset
UTC-05:00
Standard · -05
Daylight saving
Not observed
Year-round standard time
IANA zones
2
None observe daylight saving
DST offset
—
No summer variant
About AST
A fixed, year-round offset.
Acre Standard Time (AST) is a fixed clock — there are no daylight‑saving surprises, no twice‑yearly jumps; Brazil’s state of Acre and the far west of Amazonas stay at UTC‑05:00 all year.
IANA zones · the technical identifiers
The 2 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.
Where AST is used
One country.
Same offset · UTC-05:00
Other zones at UTC-05:00 right now.
These named zones share AST's offset today. When daylight saving rules differ, they drift apart for part of the year.
Convert
AST to the world's clocks.
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 does AST never change for daylight saving?
- Neither member zone observes daylight saving time. Their last clock change was on November 10, 2013, when they returned to UTC‑05:00 after more than five years on UTC‑04:00.
- How many zones share Acre Standard Time?
- Only two: Eirunepe and Rio Branco, both in western Brazil.
- Is AST the same as Eastern Standard Time?
- No, though they share the same offset. Acre Time is UTC‑05:00 all year, like Eastern Standard Time, but it has no daylight saving time, so it is one hour behind the US East Coast while Eastern Daylight Time (UTC‑04:00) is in effect from March to November.
- What’s special about the Acre region’s time history?
- In 2008 Acre and western Amazonas moved to UTC‑04:00, but after a 2010 referendum in Acre, both returned to UTC‑05:00 on November 10, 2013. Rio Branco last used daylight saving time in 1988, and Eirunepe in 1994.
- Do any member zones ever deviate from UTC‑05:00?
- Never; since the 2013 transition, both Eirunepe and Rio Branco march in perfect UTC‑05:00 step.
- Which countries use Acre Standard Time?
- Brazil alone: the state of Acre and the far west of Amazonas state.
- What’s the next time change for AST?
- None is scheduled. The last change was on November 10, 2013, and the offset has been UTC‑05:00 since.
- How does AST affect global scheduling?
- With no DST, AST offers a reliable UTC‑05:00 slot—perfect for cross‑border calls without seasonal surprises.
Source: IANA tzdb2026d · Reviewed
Free · Developer API
This time zone, as JSON.
Its defining offset, DST status and member counts, from one endpoint.
Also in the API: time zones by coordinates, conversions that flag daylight saving gaps, and abbreviations decoded.
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