THE PACIFIC AND THE DATE LINE'S ZIGZAG
Two islands, an hour apart, a day apart
The line is not straight. Neighbouring places can sit on opposite sides of the calendar.
Apia, Samoa. Pago Pago, American Samoa. About 100 km of ocean between them, and a flight of well under an hour.
Samoa is at UTC+13. American Samoa is at UTC−11 — UTC−11. The clocks differ by one hour. The calendar dates differ by a full day.
When it is Sunday morning in Apia, it is Saturday morning in Pago Pago.
Why the line zigzags
The International Date Line follows roughly 180° longitude, but it is not a straight line and it is not a treaty. No body defines or administers it.
It is simply where the offsets countries have chosen for themselves happen to meet — so it moves whenever a country changes its mind.
Kiribati, 1995. The country straddled the line and was permanently split across two calendar dates, which made government impossible. It moved its eastern islands to the western side, creating UTC+14 and making Kiritimati one of the first places on earth into each new day.
Samoa, 2011. It skipped 30 December entirely — the date simply did not happen — to move from UTC−11 to UTC+13, aligning its working week with Australia and New Zealand rather than the United States. American Samoa, being a US territory, stayed put. Hence the neighbours a day apart.
The full spread
| Place | Offset | Notes |
|---|---|---|
| Kiritimati, Kiribati | UTC+14 | First inhabited place into a new day |
| Samoa, Tonga | UTC+13 | |
| Chatham Islands | UTC+13:45 | 45-minute offset |
| Auckland, Fiji | UTC+12 | |
| Niue, American Samoa | UTC−11 | Last inhabited places |
From Kiritimati to Niue is a 25-hour spread among inhabited places — more than a full day. Counting uninhabited US minor outlying islands at UTC−12, the full range is 26 hours.
That is why, for part of every day, three different calendar dates are in use somewhere on earth.
What it means if you deal with the Pacific
Never give a date-only deadline. "By Friday" spans two calendar days across this region, which is a genuinely large ambiguity.
Check the date, not just the time, on any booking, call or delivery. Neighbouring islands are not on the same day.
Be careful with "tomorrow" and "yesterday." Across a 25-hour spread these can refer to the same calendar date, which makes them useless as shared terms.
Flights are the strange part. Apia to Pago Pago can leave on Sunday and land on Saturday. Nothing is wrong with the ticket.
Why these choices were made
Both Kiribati and Samoa were making the same trade: alignment with trading partners beats alignment with the sun.
Samoa's economy is oriented toward Australia and New Zealand. Being 21 hours behind Sydney meant Samoan Monday was Australian Tuesday, and the countries shared only three working days a week. Moving the date line gained them two.
Related: The international date line · I land before I took off
Timezone: World Clock Widget
A world clock, converter and live day/night map for iPhone — 325 cities, offline, no account.
Figures on this page are computed from the IANA time zone database. Last generated 2026-08-18.