How do time zones work?

Travel is wonderful, but it can make communicating with your loved ones back home difficult. While you’re waiting for everyone you know to wake up so they can react to your snaps of gorgeous Buddhist temples or stunning sunsets, you might find yourself asking: just how do time zones work.

So, if you’ve ever hit a Bangkok night market or come in from post-midnight dinner in Mexico City and realised your pals are only just crawling out of bed, and wondered why, read on to find out how time zones work!

Who decided on time zones?

Once, time was a lot more specific to a location. Some places would have dedicated sundials, whereas others would use landmarks like church steeples and shadows to figure out what the time was. So, a settlement might have noon at a different time to one just a few miles away, because of the way the sun moves across the sky.

For most of human history, this wasn’t a problem. However, when trains – and train timetables – became a reality, this quirk became a real issue. To stop people and cargo missing their connections, it was decided that there should be some “buffer” in the time, and that the world should be split up into different sections which shared a time. This meant some places would lose or gain a few minutes, but it was better than the alternative. At first this was done on a local scale, but it soon became clear a global standard was needed.

A few people have a claim to being the inventors of time zones, but like many concepts, it seems to have sprung into being at a similar time in a few different places in the world. The Royal Observatory, Greenwich, first defined what would become Greenwich Mean Time (GMT) back in the 1670s, under the Royal Astronomer John Flamsteed. In the following decades, sailors across Britain’s vast empire followed that, but that wasn’t a time zone really – more of a timeline.

Some argue that Italian mathematician Quiricio Filopanti was the first to come up with the idea of global time zones, in his 1858 book Miranda!. However, most see Canadian Sir Sandford Fleming as the creator of worldwide standard time. He pushed for his system to be implemented at a number of well-attended conferences on the topic, and although to this day there is no global standard for representing time zones, his is by far the most commonly used.

Now, all nations have some kind of standard time zone, even if we haven’t decided on an international one.

How do time zones work?

Time zones generally use the following measurement: 15 degrees of longitude equals one hour. Some places split it on an hourly basis, and split it into half or even quarter hour sections.

Time moves backward the further west you go, so it will always be earlier in the day in Japan than Germany. But, of course, the earth is round, which means at some point the clock resets. This happens at a point between the north and south poles, known as the International Date Line. In theory, this is placed at 180 degrees of longitude. Generally, it is seen as running between the U.S and Russia in the north, and different Pacific islands in the south. However, the exact location of the line, like most dividing features on a globe, is very much contested. Who knew telling time around the world could be so political?

When do time zones not work?

Different time zones are decided in different ways, and not always to the delight of people who have to live under them. China and India, for example, have one time zone, despite both being incredibly vast countries. That means in Western parts of China you can have blazing sunlight when you’d expect the oranges and pinks of sunset.

Certain towns in massive countries like the US, Australia, and Russia are an hour apart from nearby settlements too, which can lead to a lot of confusion for people who traverse the two every day. After all, the time zone line has to go somewhere.

Which time zone starts the day first?

UTC+14 (14 hours ahead of the Greenwich Mean Time) is the “earliest” time zone. This zone is only used by a tiny island called Kiribati, which is located in the Micronesia subregion of Oceania.

What is the logic behind time zones?

The logic behind time zones is that a town or city being a few minutes out of when they would have traditionally thought the time was better than having a gaggle of disparate times between nearby locations.

Do time zones change by the hour?

Generally speaking time zones are split up into hours, but there are some places that have 30 or 45 minute time zones, notably Australia and Canada. India is also five and a half hours ahead of GMT.

How do time zones work when flying?

Because we move across the globe so quickly while flying, time zones are easily bypassed. This means you can wake up in London, grab an early breakfast, get on a flight, then have a late breakfast in New York. This is the primary cause of “jet lag,” which tends to occur when moving across 3 or more time zones, but can affect anyone.

How does daylight savings affect time zones?

Daylight savings moves the time back or forward in various countries, but not all subscribe to it, which means that the time difference between countries can grow or shorten depending on the time of year.