Technical Specifications & Standards
Official chronometric properties, ISO standards, and international database registry identifiers for Chatham Island Standard Time:
Daylight Saving Time (DST) Transitions
⬆️ Spring Forward (Clocks Advance)
Clocks advance 1 hour to CHADT on the last Sunday in September at 02:45
⬇️ Fall Back (Clocks Return)
Clocks return 1 hour to CHAST on the first Sunday in April at 03:45
Observing Jurisdictions & Subdivisions
1 Sovereign NationsSovereign nations, administrative subdivisions, and regional territories officially operating under CHAST:
Regional Subdivisions & Territory Details
Financial Markets & Trading Hours
Coordinates crayfish exports, wool farming, and remote maritime conservation 800 km east of Christchurch.
Local Hours: 08:30 - 16:30 CHAST
UTC Window: 19:45 - 03:45 UTC
Major Cities in CHAST
Primary metropolitan centers and financial hubs observing this time zone:
Adoption History & Astronomical Facts
Year Established: 1956
The Chatham Islands established an official 45-minute advance ahead of mainland New Zealand (NZST, UTC+12) in 1956 to reflect their longitude at 176° West.
The Chatham Islands observe a 45-minute offset, so when it is 12:00 in Auckland, it is 12:45 in Waitangi.
Frequently Asked Questions about CHAST
What is Chatham Island Standard Time?
Chatham Island Standard Time (CHAST) is UTC+12:45, observed during winter in the Chatham Islands.
Why do the Chatham Islands have a 45-minute offset?
The islands are located about 800 kilometers east of mainland New Zealand, and UTC+12:45 aligns clock time with local solar noon.
Does Chatham Island observe daylight saving?
Yes. In summer, clocks advance 1 hour to CHADT (UTC+13:45).