Where time gets weird

Time isn't as linear as you would think.

Time zones are a fundamental part of how we organize our world, ensuring that our clocks align with the position of the sun. The whole concept seems straightforward (different places have different times based on their location, right?) but the reality of time zones is far from simple. In fact, time zones are shaped by politics, history, and geography more than by the logical division of the Earth into 24 equal segments, one for each hour of the day. Oh and there’s that whole International Date Line thing. But first, let’s start where where time zones even originated from!

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The origins of time zones

Greenwich, England. Photo by Robert Bye on Unsplash

For much of human history, time was a local affair, based on the sun’s position in the sky. Which meant that, each individual town would have its own time! If you thought that time zones are complicated today, it’s surprisingly much easier than it used to be.

It wasn’t until the 1800s, with the expansion of railroads and telegraphs, that the need for a standardized system became clear. When people could travel faster than the day could change, there became a need to keep time standardized. And so, the modern system of time zones was formalized in 1884 at the International Meridian Conference, where delegates from 25 countries agreed to establish Greenwich Mean Time (GMT) as the global reference point. The Royal Observatory in Greenwich, England was chosen at the time because of Britain’s maritime dominance and by the late 1800s, most navigational charts used Greenwich as a baseline anyways so it made a certain amount of sense.

This decision laid the foundation for the global timekeeping system we use today. However, while the Earth rotates through 24 hours, we don’t actually have just 24 time zones.

24 hours, 40 time zones

Here’s a fun one! Given the fact that we have 24 hours in a single day, you might expect there to be 24 time zones, one for each hour of the day, but in reality, there are 40. This discrepancy arises from a mix of political, practical, and geographic factors. Some regions use half-hour or even 45-minute offsets instead of whole hours, while others adjust their time zones to better fit economic or cultural needs.

One of the most perplexing examples of this is the International Date Line.

The International Date Line: where time jumps a day

The International Date Line is an imaginary boundary in the Pacific Ocean where the calendar date changes. If you cross it moving east, you go back a day. Moving west, you jump forward. Which feels backwards as well just given my own natural inclination to interpret moving right (east) as progressing. But whatever!

This line roughly follows the 180th meridian but zigzags to avoid splitting countries into different calendar days. For instance, Kiribati moved its time zone to ensure its islands were among the first places in the world to see the new day. Similarly, Samoa switched sides of the Date Line in 2011 to align better with its trading partners, putting it nearly a full day ahead of its neighbor and sibling, American Samoa. The Diomede Islands are another oddity along the line: Big Diomede (Russia) and Little Diomede (U.S.) are just a few miles apart, yet they are nearly 24 hours apart in time, earning them the nicknames “Tomorrow Island” and “Yesterday Island.”

Despite the seemingly drastic calendar shift, crossing the Date Line only changes the time by an hour.

The North and South Poles: time gone wild

Antarctica. Photo by Cassie Matias on Unsplash

At the North and South Poles, time zones become meaningless. Since all longitudinal lines converge at the poles, it’s technically possible to walk through all 24 time zones in just a few steps. To further complicate things, the poles experience six months of continuous daylight followed by six months of darkness, eliminating the usual cues for timekeeping.

To keep things manageable, research stations at the South Pole follow New Zealand Standard Time, since most supplies come from New Zealand. Arctic bases typically adopt the time zones of their home countries or supply hubs. In practice, timekeeping at the poles is more of a convenience than a necessity.

China: one time zone for a massive country

Beijing, China. Photo by Henry Chen on Unsplash

China, which spans roughly 5,000 kilometers from east to west, should logically have five time zones. Instead, the entire country operates on Beijing Time (UTC+8). This policy was implemented in 1949 to promote national unity, but it creates bizarre situations in western regions like Xinjiang, where the sun might rise at 10 a.m. in winter or set close to midnight in summer. Many locals in Xinjiang use an unofficial “Xinjiang Time,” two hours behind Beijing, leading to a strange dual-clock system within China, though this can and does lead to residents getting in trouble.

Half-hour and 45-minute time zones

Kathmandu, Nepal. Photo by Raimond Klavins on Unsplash

Most time zones shift in full-hour increments, but a handful of places operate on half-hour or even 45-minute offsets. These include:

• India (UTC+5:30): A colonial-era compromise between Bombay and Calcutta’s local times, retained after independence.

• Iran (UTC+3:30) and Afghanistan (UTC+4:30): A mix of geographic positioning and national identity.

• Myanmar (UTC+6:30): A holdover from British colonial rule.

• Nepal (UTC+5:45): One of the world’s most unusual time zones, chosen to distinguish itself from neighboring India and China.

Australia’s Strange Time Zones

Central Australia. Photo by Daniele Nabissi on Unsplash

Australia has some of the strangest time zones in the world. Central Australia follows a half-hour offset (UTC+9:30) rather than a full hour, a decision that helps balance sunrise and sunset times. But an even weirder quirk exists in Eucla, a small town near the South Australia-Western Australia border, where the time zone is set at UTC+9:45—a 45-minute offset that is used unofficially by locals and businesses.

Arizona’s time-jumping trick

Phoenix, Arizona. Photo by Chris Tingom on Unsplash

Arizona stands out in the United States by refusing to observe daylight saving time. As a result, it effectively jumps between time zones depending on the season. In winter, it aligns with Mountain Standard Time (UTC−7), but in summer, it aligns with Pacific Daylight Time (UTC−7) while neighboring states shift an hour forward. To add another layer of confusion, the Navajo Nation within Arizona does observe daylight saving time, while the Hopi Reservation—entirely surrounded by the Navajo Nation—does not.

Why time zones are so weird

Time zones are meant to align our daily lives with the movement of the sun, but in practice, they are shaped by whatever any given political body wants. From countries that defy logic by using a single time zone across vast territories to tiny regions that insist on hyper-precise offsets, our global clock is far from a perfect geographic system. And as long as humans continue to adapt time to their needs rather than the other way around, time zones will remain one of the weirdest parts of our world.