Why there is no official time
Time zones are normally set by governments for the people living in an area. Antarctica has no permanent residents, and the Antarctic Treaty of 1959 set aside the territorial claims made by several countries. As a result, there is no authority that sets a time zone for the continent as a whole.
There is also a geographic problem. Time zones are based on lines of longitude, and in Antarctica those lines converge toward the South Pole. A strict system of zones would produce narrow wedges near the pole, some of them only a few kilometers wide, which would make no sense for anyone working there.
How stations choose a time
In practice, each research station chooses its own time. The most common reasons are:
- Supply links. Stations often keep the time of the city their flights and ships leave from, so that schedules, calls and logistics line up.
- The home country. Some stations keep a time close to their national capital to make communication with home easier.
- Local daylight. Some stations simply use the offset that fits their longitude.
The result is a patchwork of offsets, sometimes with neighboring stations keeping different times.
Examples
| Station | Operated by | Time used |
|---|---|---|
| McMurdo Station | United States | New Zealand time |
| Amundsen-Scott South Pole Station | United States | New Zealand time |
| Scott Base | New Zealand | New Zealand time |
| Palmer Station | United States | A time based on Chile’s, matching its supply route |
McMurdo and the South Pole station are run by the United States, yet they keep New Zealand time because their flights operate from Christchurch. They even follow New Zealand’s daylight saving time. Read more in the New Zealand time zone history.
Other stations, run by countries such as Australia, Argentina, Chile, the United Kingdom, Russia and China, each set their own clocks. Some have changed their offsets over the years, so it is best to check a reliable, up-to-date time zone source before calling a particular station.
Daylight and darkness
Clock time means less than usual in Antarctica because of its extreme daylight cycle. Near the coast, summer brings weeks of midnight sun and winter brings weeks of polar night. At the South Pole itself, the sun rises once a year, around the September equinox, and sets once a year, around the March equinox, so there are roughly six months of daylight followed by six months of darkness.
Because of this, people at stations rely on the clock, not the sun, to structure their days. Meals, work shifts and sleep follow the station time, whatever the sky is doing. You can learn how the seasons drive these extremes on the seasons page and compare day lengths elsewhere with the sunrise and sunset times.
Time zone databases
Software still needs a time for Antarctic stations, so the IANA time zone database, which computers and phones use, has entries for several of them under names such as Antarctica/McMurdo and Antarctica/Palmer. These entries record the time each station actually uses, not a theoretical zone based on longitude.
The South Pole and every time zone
Because all meridians meet at the pole, the South Pole technically belongs to every time zone at once. That is why the choice of time there is purely practical. Following New Zealand time keeps the station in step with the people and aircraft that supply it.
Why it matters
For most people, Antarctic time zones are a curiosity. For researchers, pilots and supply teams, they matter a lot: a flight scheduled in one station’s time must be translated correctly for another. Expressing times in UTC is a common way to avoid confusion. To compare any time across zones, use the world clock or read UTC vs GMT for background on the world’s reference time.