Have you checked your International Dateline map data layer recently? Chances are that it’s incorrect! Yes indeed, the dateline has changed and you may not know about it. That’s because in December, 2011 the tiny Island nation of Samoa decided they were on the wrong side of the dateline… so they changed it!
The skinny… An interesting mapping story that you may not have heard about over the New Year as Samoa decided last year that they were on the wrong side of the International dateline. Indeed a good move for Samoa as when you take into account their relationship with Australia they were essentially missing out on 2 full days of business due to their geographical placement relative to the dateline. In a bold move, and unfortunate for those who celebrate their birthday on Dec 30th, Samoa made the change in 2011 and Samoans went to bed Dec 29, 2011 and woke up the following morning on December 31, the same day as their mates in Australia!

Immediately to the left of the International Date Line the date is always one day ahead of the date (or day) immediately to the right of the International Date Line in the Western Hemisphere. Note that Tonga and Samoa have the same time but are one day apart, as Samoa is in the Western Hemisphere, on the opposite side of the International Dateline from Tonga. As you travel further west, note that the time in Fiji is one hour earlier than Tonga. You will also notice that Hawaii, further to the east of Samoa, is one hour later in time. Source
From BBC News Asia… “The change comes 119 years after Samoa moved in the opposite direction. Then, it transferred to the same side of the international date line as the United States, in an effort to aid trade.”
Thanks to James Whately and his recent presentation “The 5 Word of Mouth Moments of 2011” for the inspiration for this post