Time zone · Oceania
CHST
Chamorro Standard Time
Chamorro Standard Time (CHST) keeps Guam and the Northern Mariana Islands locked to a steady UTC+10:00 year-round—no daylight saving shifts to worry about, making it refreshingly simple to coordinate across the western Pacific. Whether you're calling Saipan, Hagåtña, or a partner in Tokyo, the clock never springs forward or falls back, so your meetings stay predictable.
Friday, October 16, 2026
Current offset
UTC+10:00
Standard · ChST
Daylight saving
Not observed
Year-round standard time
IANA zones
2
None observe daylight saving
DST offset
—
No summer variant
About CHST
A fixed, year-round offset.
Chamorro Standard Time (CHST) keeps Guam and the Northern Mariana Islands locked to a steady UTC+10:00 year-round—no daylight saving shifts to worry about, making it refreshingly simple to coordinate across the western Pacific. Whether you're calling Saipan, Hagåtña, or a partner in Tokyo, the clock never springs forward or falls back, so your meetings stay predictable.
IANA zones · the technical identifiers
The 2 zones that resolve to CHST.
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 across CHST
Local time, city by city.
2 cities
Where CHST is used
2 countries.
Same offset · UTC+10:00
Other zones at UTC+10:00 right now.
These named zones share CHST's offset today. When daylight saving rules differ, they drift apart for part of the year.
Convert
CHST to the world's clocks.
Frequently asked questions
Common questions about CHST, daylight saving, and how to handle it in software. Can't find what you need? Email [email protected].
- Why doesn’t Chamorro Standard Time observe daylight saving?
- Because Guam and the Northern Mariana Islands lie well inside the tropics, daylight hours stay fairly constant year-round, so there’s little benefit to shifting clocks. The U.S. Uniform Time Act of 1966 also lets far-flung territories opt out, and both islands chose to keep one standard time.
- How does CHST compare to neighboring time zones like PGT or JST?
- ChST is one hour ahead of Japan Standard Time (UTC+09:00) and the same as Papua New Guinea Time (UTC+10:00), so Guam and Saipan share clock time with Port Moresby and Brisbane all year.
- Are there two different ‘Chamorro Time Zones’—Chamorro Standard Time and Chamorro Daylight Time?
- Guam used daylight saving time (UTC+11:00) in several years between 1959 and 1977, but it has not changed its clocks since; today only Chamorro Standard Time is in use.
- Will CHST ever switch to daylight saving?
- There are no current plans; both Guam and the Northern Mariana Islands stay on UTC+10:00 all year.
- Is ‘Chamorro’ different from ‘ChST’ in documents?
- They refer to the same UTC+10:00 zone—‘Chamorro Standard Time’ is just spelled out, ‘ChST’ is the abbreviation.
- How do you pronounce ‘Chamorro’?
- It’s “chuh-MOR-oh” (IPA: /tʃəˈmɔːroʊ/), named after the indigenous Chamorro people of the Mariana Islands.
Source: IANA tzdb2026e · 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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