Historically distinct IANA time zone
Pacific/Rarotonga
- Countries
- Cook Islands
- GPS reference
- 21.23° S, 159.77° W
- Data source
- IANA australasia
- Aliases
- None
- Rule groups
- Cook
Cook IslandsGeographic context
Where this clock belongs
The map marks the IANA reference location and associated country, not a time-zone boundary.
GPS reference: 21.23° S, 159.77° W. Associated countries: CK.
The Wikipedia link provides additional context; it is not evidence for a historical claim. Transition data comes from the IANA source file.
Notes from the time database
The story behind the clock
These source notes describe a period or rule. They do not, by themselves, establish a causal claim for a particular clock change.
Cook Is In 1899 the Cook Islands celebrated Christmas twice to correct the calendar. According to the old books, missionaries were unaware of the International Date line, when they came from Sydney. Thus the Cook Islands were one day ahead.... ... Appendix to the Journals of the House of Representatives, 1900 (page 20) ... in the Cook Island Act of 1915-10-11, online at "651. The hour of the day shall in each of the islands included in the Cook Islands be determined in accordance with the meridian of that island." so that local (mean?) time was still used in Rarotonga (and Niue) in 1915. This was changed in the Cook Island Amendment Act of 1952-10-16 ... "651 (1) The hour of the day in each of the islands included in the Cook Islands, other than Niue, shall be determined as if each island were situated on the meridian one hundred and fifty-seven degrees thirty minutes West of Greenwich. (2) The hour of the day in the Island of Niue shall be determined as if that island were situated on the meridian one hundred and seventy degrees West of Greenwich." This act does not state when it takes effect, so one has to assume it applies since 1952-10-16. But there is the possibility that the act just legalized prior existing practice, as we had seen with the Guernsey law of 1913-06-18 for the switch in 1909-04-19. Transitions after 1952 are from Shanks & Pottenger.
Original IANA source file: australasia.
A shared present
Same clock today, different past
These nearby zones follow the same current annual pattern, yet retain their own historical record.
French Polynesia · 1146 km from the reference location · Same annual clock since 1992Civil-time record
Recorded changes over time
From 1899 to 1991 · 28 recorded transitions
Recurring daylight-saving changes are grouped separately when JavaScript is available.
Notable changes
One-off changes and transitions outside the recurring seasonal rhythm.
- -10:39 · LMTStandard time applies
- -10:30 · -1030Standard time applies
- -09:30 · -0930Daylight saving time begins
- -10:00 · -10Standard time applies
- -09:30 · -0930Daylight saving time begins
- -10:00 · -10Standard time applies
Browse every recorded transition
| Local time after transition | Offset after | Abbreviation | Rule |
|---|---|---|---|
| 1899-12-25 00:00 | -10:39 | LMT | Standard time |
| 1952-10-16 00:09 | -10:30 | -1030 | Standard time |
| 1978-11-12 01:00 | -09:30 | -0930 | Daylight saving time |
| 1979-03-03 23:30 | -10:00 | -10 | Standard time |
| 1979-10-28 00:30 | -09:30 | -0930 | Daylight saving time |
| 1980-03-01 23:30 | -10:00 | -10 | Standard time |
| 1980-10-26 00:30 | -09:30 | -0930 | Daylight saving time |
| 1981-02-28 23:30 | -10:00 | -10 | Standard time |
| 1981-10-25 00:30 | -09:30 | -0930 | Daylight saving time |
| 1982-03-06 23:30 | -10:00 | -10 | Standard time |
| 1982-10-31 00:30 | -09:30 | -0930 | Daylight saving time |
| 1983-03-05 23:30 | -10:00 | -10 | Standard time |
| 1983-10-30 00:30 | -09:30 | -0930 | Daylight saving time |
| 1984-03-03 23:30 | -10:00 | -10 | Standard time |
| 1984-10-28 00:30 | -09:30 | -0930 | Daylight saving time |
| 1985-03-02 23:30 | -10:00 | -10 | Standard time |
| 1985-10-27 00:30 | -09:30 | -0930 | Daylight saving time |
| 1986-03-01 23:30 | -10:00 | -10 | Standard time |
| 1986-10-26 00:30 | -09:30 | -0930 | Daylight saving time |
| 1987-02-28 23:30 | -10:00 | -10 | Standard time |
| 1987-10-25 00:30 | -09:30 | -0930 | Daylight saving time |
| 1988-03-05 23:30 | -10:00 | -10 | Standard time |
| 1988-10-30 00:30 | -09:30 | -0930 | Daylight saving time |
| 1989-03-04 23:30 | -10:00 | -10 | Standard time |
| 1989-10-29 00:30 | -09:30 | -0930 | Daylight saving time |
| 1990-03-03 23:30 | -10:00 | -10 | Standard time |
| 1990-10-28 00:30 | -09:30 | -0930 | Daylight saving time |
| 1991-03-02 23:30 | -10:00 | -10 | Standard time |