Kiribati · 1994–1995
One country.
Two dates.
It could be Friday in one part of Kiribati while another was still on Thursday. To bring their calendars closer together, the eastern islands moved their date forward by a whole day.
4-minute read · Includes an experiment to explain the change
First: where are we?
Kiribati is an island country in the Pacific. Tarawa is in the Gilbert Islands, to the west. Kanton, in the Phoenix Islands, and Kiritimati, in the Line Islands, lie farther east. Before the change, they were on opposite sides of the date line.
Imagine working in Tarawa and phoning someone in Kiritimati on a Friday morning. It is daylight and working time there too, but the person answering is still on Thursday. You don’t have to travel to encounter the date line: a phone call will do.
Try it · one moment, three islands
It’s Friday in Tarawa. What about the other islands?
Hold the time in Tarawa at 10 am. Switch between the rules before and after the change.
Same country, different dates. Kiritimati is 22 hours behind Tarawa.
A calculated example using offsets recorded by IANA, a time zone database used by computer systems, not a reconstruction of a particular phone call. UTC is the reference used to compare local times.
The date moved forward
IANA’s record moves Kanton from UTC−11 to UTC+13 and Kiritimati from UTC−10 to UTC+14. Each is a 24-hour jump. Tarawa stays at UTC+12.
A clock can show the same time after a whole-day jump. What changes is the calendar. In our example, Kiritimati goes from 22 hours behind Tarawa to two hours ahead.
Kiribati did not adopt a single time zone. The three groups kept three different times. Nor does this mean every island always has the same date: around midnight, the day starts earlier in some places than others. See IANA’s rules ↗
The jump recorded by IANA
From 30 December to 1 January
This sequence applies to the eastern zones represented by Kanton and Kiritimati in the database. Tarawa did not skip that Saturday.
This reconstructs the time-zone record. We have not obtained the original government instrument here. A possible local implementation on 4–5 January, noted in the research file, still needs checking.
Even the database had the wrong day
For years, IANA placed the jump a day later. In February 2018, Kerry Shetline asked why the record skipped 1 January 1995 when the references he was finding pointed to 31 December.
Paul Eggert acknowledged a data-entry error and proposed a correction. The exchange lets us follow the repair of the record. It does not replace the document by which Kiribati made its decision. Read the 2018 exchange ↗
The calendar changed before some maps
In 2012, the US Department of State explained that its maps had retained the old alignment around Kiribati, with notes about the change. Its new guidance called for an update.
The guidance describes the proposed dashed line as “notional”. We cannot take those 2012 turning points and present them as an exact boundary from 1995. A civil date and a line on a map are different kinds of evidence. Read the guidance and maps, pages 1–4 ↗
A question as you read
Can a map keep an old date boundary?
Discover the answer
Kiribati changed dates in 1995, but US government maps retained the earlier line with explanatory notes. In 2012, new guidance called for an updated depiction around Kiribati, Samoa and Tokelau.
2012 mapping guidance, pp. 1–2 →Sources and what they establish
- IANA · australasia file ↗. Pacific/Tarawa, Pacific/Kanton and Pacific/Kiritimati: recorded time rules and transition date.
- tz mailing list · February 2018 ↗. Direct evidence of the database correction, not the original enactment.
- Department of State · Bulletin 31, 2012 ↗. Later mapping guidance with an explicitly notional line.