I captured the query of an anonymous reader. He or she wanted to know whether there were an islands split by time zones. I’d never pondered that before but I came up with a couple of quick examples off the top of my head. That didn’t satisfy me so I turned to a worldwide timezone map. Sure enough I came up with a few more instances. I can’t guarantee that I’ve compiled the definitive and complete list but it’s a good start. These are the obvious ones so please let me know if you find others.
Various Canadian Islands and Greenland
Canada has a whole set of islands in its northern reaches with time zone splits, theoretically. I put that disclaimer in place because the time zone concept is rather complicated in remote and borderland areas of Canada, with the "official" time zone frequently ignored. The whole wacky situation is described in Canadian Geographic, in "It’s about TIME."
We are a country of chronic lawbreakers. From east to west, Canada is neatly divided into six time zones. But many Canadians choose to make their own time and ignore the time zone boundaries. And the rule that clocks spring forward on the first Sunday in April and fall back on the last Sunday in October? In some parts of Canada, the times are never a-changin’: we all know that Saskatchewan doesn’t use daylight savings, but other pockets of the country don’t bother with it either. And while Alberta’s time-abiding citizens strictly follow Mountain Time – violators can be slapped with a $25 fine.
Yes, there are a number of Canadian islands that happen to be split by time zones on paper but I’m not sure these have much practical meaning. People in those areas will seemingly follow whatever time appears convenient.
Greenland, the world’s largest island, has four time zones. The vast preponderance of Greenland follows Coordinated Universal Time (UTC)-3. A small area located in the far northwest including the United States’ Thule Air Base observes UTC-4. Maybe that’s to make it closer in time to the eastern United States? There are also two small areas of eastern Greenland that follow UTC-1 and UTC+0 respectively. I have absolutely no idea why no portion of Greenland follows UTC-2. It seems odd. Maybe someone in the readership knows the answer.
Isla Grande de Tierra del Fuego
Isla Grande de Tierra del Fuego is the largest island in the Tierra del Fuego archipelago. This island was a topic of discussion on one of my recent articles, "Ushuaia". The time zone split follows the border between Argentina (UTC-3) and Chile (UTC-4) just like the remainder of the border between these two nations.
Borneo and New Guinea
Borneo has been split by two time zones associated with Malaysia (UTC+8) and Indonesia (UTC+7). Brunei — including it’s odd exclave — also shares a small portion Borneo but it’s just along for the ride in UTC+8.
Indonesia stretches far enough to require three time zones. It makes a second appearance on the list of islands split by time zones on New Guinea. Here it’s UTC+9 with the portion forming Papua New Guinea located in UTC+10.
I found one more example on Hispaniola which is shared by the Dominican Republic (UTC-4) and Haiti (UTC-5).
I was able to find six examples of islands split by time zone, perhaps more if one counts each of the Canadian instances separately, in just a few minutes of searching. Canada and Greenland represented instances within a single country. The other instances followed international borders.