Why Antarctica Has 10 Time Zones and No Government to Set Them

At McMurdo Station on Tuesday evening it was 6:10 p.m. At Palmer Station, run by the same government on the same continent, it was 3:10 a.m., dark and mid-shift, nowhere close to evening. Both are United States research stations in Antarctica. Neither uses Washington's clock, and they do not use each other's either.

That fifteen-hour gap between two American outposts on one continent is not a glitch. It is the closest thing Antarctica has to an honest answer for what time it is. Nobody governs the continent, so nobody has ever had the standing to draw its time zones. The U.S. Antarctic Program's own station clock makes the point without meaning to: three American bases, three different local times, one flag.

Why doesn't Antarctica have its own time zone?

Ordinary time zones exist because a government draws them: a legislature, a monarch, a colonial administrator. Antarctica has none of that. The Antarctic Treaty, signed by twelve countries on December 1, 1959, and in force since 1961, covers everything south of 60 degrees latitude and puts the whole question of who owns it in permanent suspension. Article IV is blunt about it.

"No acts or activities taking place while the present Treaty is in force shall constitute a basis for asserting, supporting or denying a claim to territorial sovereignty in Antarctica."

Antarctic Treaty, Article IV, Section 2 (1959)

Seven countries had already staked formal claims before 1959: Argentina, Australia, Chile, France, New Zealand, Norway and the United Kingdom. Some overlap outright. Argentina, Chile and the U.K. all claim slices of the Antarctic Peninsula that sit on top of one another. In February 1952, an Argentine naval party at Hope Bay fired a machine gun over the heads of a British landing party trying to rebuild a fire-damaged research hut nearby, forcing the British back onto their ship. The Falklands' governor cabled London that the episode presumably constitutes an act of war. It didn't become one. But the treaty that followed seven years later didn't settle whose peninsula it is. It just made the question illegal to pursue by force, and largely pointless to pursue by paperwork, for as long as the agreement holds.

A government issues time zones as an exercise of sovereignty. Freeze the sovereignty question and there is, quite literally, no one with the authority to set the clocks.

So who decided Antarctica needs ten time zones?

Software engineers, mostly. The IANA time zone database, the free reference file that Linux servers, Android phones and most of the internet quietly consult for the correct local time, had a practical problem: code needs a time zone string for every inhabited place on Earth, sovereignty or no sovereignty. Its maintainers settled on ten zones, one per year-round station cluster: Casey, Davis, DumontDUrville, Mawson, McMurdo, Palmer, Rothera, Syowa, Troll and Vostok. None of it is law. All of it is what happened to be convenient for people trying to make a computer report an accurate clock at the bottom of the world.

Convenient usually means one thing: match the supply line. McMurdo Station and the Amundsen-Scott South Pole Station both run on New Zealand time, not because Wellington claims them but because their flights and cargo move through Christchurch. Paul Siple, the first station commander at the Pole, wrote that he would have preferred to keep Greenwich Mean Time there, a neutral, apolitical choice, but gave in because McMurdo Sound, his supply route, was already running on New Zealand's clock. Six decades later, the Pole still is — right down to observing Christchurch's daylight saving.

Rothera, Britain's largest Antarctic base, doesn't run on London time either. It's fixed at UTC-3 year-round, in step with Chile and the Falklands, because that's the direction its planes and ships actually come from. The country with one of the oldest continuous territorial claims on the continent doesn't sync its flagship station to its own capital.

What time zone is the South Pole in?

New Zealand's: NZST or NZDT, UTC+12 or UTC+13 depending on the season, because Amundsen-Scott follows Christchurch's clock along with McMurdo. Vostok, the Russian station roughly 900 miles away and one of the coldest inhabited places on Earth, keeps nothing like it. It has run on UTC+7, gone dark during a 1990s closure, and shifted to UTC+5 in December 2023, timed to match the nearby Progress base and its supply convoys, not any reasoning tied to longitude. The time zone database's own maintainer notes, after years of conflicting accounts from scientists who wintered there, concede the obvious: nobody was ever fully sure what time Vostok kept.

Casey, Australia's station, has swung between UTC+8 and UTC+11 more than a dozen times since 2009 as the Australian Antarctic Division nudges it in and out of sync with mainland daylight saving, most recently settling back at UTC+8 in March 2023. Norway's Troll station is stranger still. Its clock loosely tracks Central European time, including a version of European daylight saving whose switch dates trace not to Oslo but to a 2014 email exchange in which a database volunteer, lacking better information, simply guessed at plausible dates. Those guessed dates are still what Troll runs on today.

Does any country actually own Antarctica?

Legally, no, and that's the point of the treaty, not a side effect of it. The claims still exist on paper. Argentina, Australia, Chile, France, New Zealand, Norway and the U.K. haven't withdrawn them, and the treaty doesn't ask them to. It just bars anyone from treating a base, a flag-raising or a survey as evidence for or against a claim while the agreement is in force. Twenty-nine countries now hold full voting rights as Consultative Parties, and 21 more have joined as non-voting Acceding Parties with no claim to defend, which is a large part of why nobody has needed to reopen the sovereignty fight since 1961.

Time zones turned out to be the one everyday problem that sovereignty-freezing couldn't dodge. Somebody still has to know when the resupply plane lands, when to call home, when the sun that hasn't set in weeks counts as morning. Governments could have fought over that too. Instead the job fell, by default, to whichever country flies in the food, and after that, to whoever happened to be maintaining a piece of open-source software when the question came up. Six decades after twelve nations agreed not to argue about who owns the ice, the argument that never happened has been replaced by ten separate, quietly arbitrary answers to a much smaller one. At Vostok, even that answer keeps changing.