Time zone · Oceania
ACWST
Australian Central Western Standard Time
Australian Central Western Standard Time (ACWST) is a little-known but fascinating half-hour offset (+08:45) used by a handful of remote settlements in Western Australia—most famously Eucla—sitting along the border where the longitudinal divide between Western and Central Australian time zones would otherwise run straight through communities that live, work and trade across the line.
Saturday, June 6, 2026
Current offset
UTC+08:45
Standard · +0845
Daylight saving
Not observed
Year-round standard time
IANA zones
1
None observe daylight saving
DST offset
—
No summer variant
About ACWST
A fixed, year-round offset.
Australian Central Western Standard Time (ACWST) is a little-known but fascinating half-hour offset (+08:45) used by a handful of remote settlements in Western Australia—most famously Eucla—sitting along the border where the longitudinal divide between Western and Central Australian time zones would otherwise run straight through communities that live, work and trade across the line.
IANA zones · the technical identifiers
The zone that resolve to ACWST.
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 ACWST is used
One country.
Frequently asked questions
Common questions about ACWST, daylight saving, and how to handle it in software. Can't find what you need? Email [email protected].
- Why is ACWST only UTC+08:45 instead of a round number?
- The +08:45 offset is a practical compromise between Australian Western Standard Time (+08:00) and Australian Central Standard Time (+09:30), created for communities whose daily life and commerce naturally span the border between these two time zones.
- Are there many places that use ACWST?
- Virtually none beyond Eucla and its immediate surroundings; it’s one of the world’s rarest time codes, representing a tiny pocket of Australia’s vast interior where local needs outweigh time-zone neatness.
- Does ACWST observe daylight saving time?
- No—ACWST has never observed daylight saving, making it one of the few truly ‘set-and-forget’ regions in a country where several mainland zones clock forward and back every year.
- How long has Eucla been using this unusual offset?
- Eucla has kept the +08:45 offset for most of the 20th century; a formal national rule change adopted it universally across Australia/Eucla only in 2009, solidifying what locals had practiced all along.
- What’s it like scheduling calls from ACWST?
- You’ll need to add an extra mental step: it’s three-quarters of an hour ahead of Perth but still 45 minutes behind Adelaide—perfect for tri-country conference calls that straddle three legal jurisdictions.
- Do maps show ACWST?
- Most maps just shade it under Western or Central, so it’s often invisible unless you specifically seek out time-zone boundary maps—a testament to its niche role in Australian geography.
- Why not just switch to a standard zone?
- Eucla’s social and economic ties sit between Perth and Adelaide; adopting a 45-minute offset neatly bridges those two spheres of influence without forcing the town to fully commit to one large city or the other.
- Is ACWST likely to ever change?
- Don’t bank on it—barring a broader review of Australian time zones, Eucla’s ‘in-between’ offset will remain a quirky fixture on time-zone maps.
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