The Island That Lost A Day

Shakti Kumar

4 min readOct 11, 2022

In my last post, I wrote about latitudes, longitudes, what are time zones and what causes the sun to set late in Mumbai

In this post, I will write about 2 very interesting islands:

One island which lost an entire day from their calendar
Another pair of islands just 4 kms apart but 21hrs apart in time

The culprit in both these cases is the same — The International Date Line (IDL). First, let us look at what this IDL is

The International Date Line (IDL)

The International Date Line, also known as the IDL, is an imaginary line that lies 180 degrees to the east or west of the Greenwich Meridian Line (the 0 degree line).

Simply put, the IDL separates 2 consecutive days. Moving across the line would account for a gain or loss of 1 day depending on which direction you travelled. If you travelled from east to west (left to right), you would lose a day whereas if you travelled from west to east (right to left), you would gain a day

Though called a line, if you have a look at the map above, you can see that it is not exactly a line in the strict sense. It has gone through a lot of changes in its shape since it has passed through many cities and countries (in some instances cutting through cities in such a manner that half the city would be in one time zone while the other would be in a different time zone)

Because of this, some countries have made the shift from one side to the other in the past — resulting in the loss/gain of a day. One such country was the island of Samoa

The Island Of Samoa — Why They Lost A Day

Samoa is an island located nearly 32 kms to the east of the IDL and is quite close to Australia. While Australia lies to the east of the IDL, Samoa island was located to the west of the IDL. In order to be in the same time zone as Australia & New Zealand with whom they carry out a lot of trading activities, they decide to shift their time zones

In the words of Samoan Prime Minister Tuilaepa Sailele Malielegaoi

While it’s Friday here, it’s Saturday in New Zealand and when we’re at church Sunday, they’re already conducting business in Sydney and Brisbane.
Samoan Prime Minister Tuilaepa Sailele Malielegaoi

This change was effected from 29th December 2011 wherein Samoa moved a day forward directly since they shifted from west of the IDL to the east of the IDL. In doing so, they directly jumped from 29th Dec (Thursday) to the 31st Dec (Saturday), skipping a day in between (30th Dec). Sad indeed for those whose birthdays fell on 30th Dec in Samoa!!!

After this change, Samoa, which was 21 hours behind Sydney was 3 hours ahead of Sydney after the change

A similar decision was taken by Tokelau island, which is close to Samoa islands

Below is an intresting case of a pair of islands known as Diomede Islands — a pair of islands which are hardly a few kms apart in distance but nearly 1 day apart in time!!! Reason — the IDL

So Close Yet So Far — The Diomede Islands

The Diomede Islands are a pair of islands located in the Bering Strait between Alaska & Siberia. They are known as the Big Diomede (on the Russian side) & Small Diomede (on the side of Alaska) islands

Though both the islands are separated by a mere 3.8 kms at their closest points, the International Date Line runs exactly between them. While the Big Diomede is located at GMT +12 timezone, the Small Diomede is located at GMT -9 timezone, causing the 21-hour difference in time between both the islands

Another interesting aspect of time & time zones is the concept of Daylight Saving Time or known as DST. However, it needs a separate post of its own which I shall write soon

Thanks for reading!!!