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Time Zones In The World: The Ultimate Guide 2023

How Many Time Zones Are There In The World?

When it comes to understanding world time, most people don’t know what are the world time zones. Have you ever traveled to another place and experienced a time change?

It’s easy to forget about time zone when travelling by plane over long distances. Maybe you know someone who lives far away and is a few hours ahead of you. While it may be Monday where you live, it may be Tuesday or even Sunday where the person you are talking to lives.

In other words, your today is somebody’s tomorrow, and someone’s yesterday may be your now. It may look like the person has traveled through time, but this is simply because we live in different time zones global.

Having different time zone means that no matter where you live on the planet, your noon is the middle of the day when the sun is highest, while midnight is the middle of the night. The differences in time zone have an interesting effect. We’ll give a brief overview of what the actual time zones are around the world and how they work in reality.

The Earth completes one full spin every day which is equal to 360 degrees. If you divide 360 degrees by 24 hours, it will result in an hourly rotation of 15 degrees, which is the width of each time zone. However, the International Date Line (IDL) creates 3 more time zones of the world.

Also, several time zones are only 30 or 45 minutes apart, increasing the total number of standard time zone even further. There are many more than 24 time zones, because every country may have a particular standard time zone, which is convenient for its international cooperation.

According to our list of world time zone which is based on IANA time zone database, there are about 200 time zones in the world. Time zones may be confusing at first, but once you figure out how standard time works, it’s just a matter of calculating the differences between the hours ahead or behind.

In this ultimate guide you will learn how many official time zones are in the world with all offsets, names, abbreviations, meanings, main countries, states and cities.

Abbreviations For Time Zones

Abbreviations For Time Zone

When on Earth the sun is at its height it is 12 o'clock or noon and the tradition of many peoples dictates that this is the official lunch time. Due to the spherical shape of the Earth, the sun's rays are most intense at the location closest to the sun.

As the Earth rotates around its axis, there are always other parts of the globe that are living in the morning, afternoon or evening. Before the Industrial Revolution, when life was dominated by agriculture and crafts, sowing, fertilizing and harvesting times were important.

With the spread of the telegraph and the construction of railroad networks in the 19th and early 20th centuries, communication and travel gained new dimensions - and new problems. With the progress of technology and science and as the world approached by means of faster and faster means of transport, people started to think about how to control the problem of time.

Before the creation of standard time zone, each place had its own time. Time zones are an invention of modern times and are usually represented by alphabetic abbreviations like "EST", "CET" and "CST".

Time Zones Abbreviations List:

Below is a list of the main abbreviations for time zones in the world:

Time Zone UTC Offset

Such designations predate ISO 8601 and the Internet age, they were sufficiently unambiguous for many practical uses within a national context.

But its ambiguity explains its deprecation in the internet age, when communications more often than not cannot rely on the implicit geographic context to provide some of the meaning.

For example, "CST" can stand for China Standard Time (UTC+8), Cuba Standard Time (UTC−5), and (North American) Central Standard Time (UTC−6).

These abbreviations for time zones now are not part of the ISO 8601 international date and time standard and their use as the sole designator for a time zone is discouraged.

Time Zones By Country

Time Zone By Country

Theoretically, each 1-hour time zone is 15 degrees wide, indicating a 1-hour difference in mean solar time. As can be seen from the map above, some time zones seem to defy logic and were primarily designed by national or regional governments to facilitate trade and administration.

Actual boundaries on a time zone map are designed to match domestic and international boundaries and rarely exactly match 15 degree time zone boundaries. Some geographically large countries like India and China only use 1 time zone, while it would be natural to expect several.

As a consequence, the day starts very late in some parts of the country, so the people who live there have had to find a solution to adjust their lives to the new time system. Because the official time is so out of step with sunrise and sunset, many non-Chinese residents ignore Beijing time and use their own time zone.

Some regions have just changed their business hours to a more reasonable time that more closely matches the actual solar time. And some cities have even implemented their own unofficial hours. The Afghanistan-China border marks the greatest terrestrial time zone difference on Earth, with a 3.5 hour difference between Afghanistan's UTC+4:30 and China's UTC+8.

But even after implementing and experiencing certain drawbacks, there are countries that want to repeat China's experience. Most large countries that span a range of longitudes have multiple time zone. This ensures that civil time is not too far from local solar time.

Apparent solar time is the time measured by the position of the sun, where noon is the instant when the Sun crosses the local meridian and reaches its highest point in the sky. Average solar time is more convenient for timekeeping around the world and is more universal as it takes into account the actual length of the average day.

The time zones around the world differences can be huge, and some countries like Russia have as many as eleven time zones within their territory. The US law identifies nine standard time zone which include its territories, and there are an additional two time zones that are unofficial.

France observes twelve time zones, mainly because it has many overseas territories.

Time Zones List by Country:

Below is a list of the main countries worldwide in each UTC offset:

Country UTC Offset

Ideal time zone, like nautical time zone, are based on the mean solar time of a particular meridian located in the middle of that zone with boundaries located 7.5 degrees east and west of the meridian.

In practice, however, many time zone boundaries are drawn much further west, and some countries are located entirely outside their ideal time zone. For example, although the Prime Meridian (0°) passes through Spain and France, they use mean solar time of 15 degrees east (Central European Time) instead of 0 degrees (Greenwich Mean Time).

France previously used GMT, but it was changed to CET (Central European Time) during the German occupation of the country during World War II and did not return after the war. Likewise, before World War II, the Netherlands observed "Amsterdam Time", which was twenty minutes ahead of Greenwich Mean Time.

They were forced to follow German time during the war and kept to it afterwards.

Time Zones By State

Time Zone By State

In some countries current use of time zone tends to more often follow state boundaries and subdivisions rather than standard parallels. Keeping the same schedule is more convenient in nearby economic or political areas.

During the summer period, some would say California and Arizona are in the same time zone, but the correct way to say it is that California and Arizona now have the same local time. As California local time during daylight saving time is UTC-7 but its standard time is UTC-8.

On the other hand, Arizona's local time is always UTC-7 because it does not observe daylight saving time.

Therefore, it remains on standard time throughout the year.

Time Zones List by State:

Below is a list of the main states worldwide in each UTC offset:

State UTC Offset

Most of Alaska uses Alaska Time, which covers three standard time zones right now. The state used two time zones until 1983, when it placed the capital, Juneau, in the same time zone as the more populous Anchorage and Fairbanks.

A lot of weird time zone also exist in Australia, where the states and central territories of South Australia and the Northern Territory must follow UTC+9. But instead they follow UTC+9:30 to minimize the gap and interruption when going to the eastern states.

There is no discrete boundary between these time zone, so you can often rotate your clocks back and forth by 1.5 hours in these areas.

At Gold Coast-Tweed Heads, during the summer you may cross the border unexpectedly, you may have traveled an hour ahead or behind.

Time Zones By City

Time Zone By City

Did you know that it is possible to time travel between two global cities?

If you take a flight from Sydney (Australia) to Los Angeles (USA) at lunchtime today, you will arrive at your destination early in the morning on the same date as today. That is, in a way you traveled back in time, when you landed on the west coast of the USA and lived twice the morning on the same calendar date.

In the meantime, you can also take a 12-15 hour flight from the US west coast to Japan or Hong Kong late in the evening and land there in the morning two days later. Even just crossing from one time zone to another can be confusing as you can still arrive before you leave, such as when flying from Minsk (Belarus) to Warsaw (Poland).

You don't even need to fly or travel from east to west. The same goes for taking the bus heading north from Utsjoki (Finland) to Tana (Norway).

Time Zones List by City:

Below is a list of the main global cities in each UTC offset:

City UTC Offset

Crossing from Kirkenes to southern Russia (November to March) you lose two hours in addition to travel time. If your trip has time zone complexities or potential impacts on your health or comfort, consult an expert when planning your trip.

In different parts of each time zone, sunrise and sunset can occur at very different times than you are used to. It might be a good idea to check the sunrise and sunset times for the time of year you will be traveling to your destination.

Time Zones By Population

Time Zone By Population

Which time zones near me will bring the largest population?

Typically, a uniform default time is maintained in each section to track the day and night cycle. This means that people in each geographic region within a time zone use the same time. The default time zone is a region where local or national authorities unify the time for a specific purpose.

If you are in another part of the world, family and friends should be aware of this when contacting you. You don't want them calling you in the middle of the night because they don't know the time difference.

If people around the world were grouped according to the time zone they are in, there would be one that would cover the largest population. The second time zone with the largest population is UTC+5:30, covering around 1.4 billion people worldwide.

The time zone covering the largest population is UTC+8, covering around 1.7 billion people worldwide.

A number equivalent to almost 24% of the world population.

Time Zones List by Population:

Below is a list of the main time zones by population:

UTC Offset Population
  • UTC+8 China 1.7 billion
  • UTC+5:30 India 1.4 billion

Currently, all nations use standard time zone for secular purposes, but not all apply the concept as originally conceived. Some countries, such as China and India, use a single time zone, although the extent of their territory far exceeds the ideal 15° of longitude for an hour.

Other countries, such as Spain and Argentina, use compensation based on standard hours, but not necessarily those that would be determined by your geographic location. The consequences, in some areas, can affect the lives of local citizens and, in extreme cases, contribute to larger political issues, as in western China.

Several countries and subdivisions use half-hour or quarter-hour deviations from standard time. Each country can have a specific default time zone if it is more convenient for your worldwide cooperation.

Time Zones Names

Time Zone Names

Around 1900, almost all inhabited places on Earth adopted a standard time zone, but only a few of them used a time offset from GMT. Many have applied the time at a local astronomical observatory to an entire country, without any reference to GMT.

It took many decades before all time zone were based on some standard offset from GMT or Coordinated Universal Time (UTC). By 1929, most countries had adopted time zone, although some countries such as Iran, India and parts of Australia had time zone with an offset of 30 minutes.

Nepal was the last country to adopt a standard offset, changing it slightly to UTC+05:45 in 1986. While many time zones have descriptive names used by people, they are less ambiguously identified by their relationship to UTC.

Time Zones Around The World:

Below is a list of the main time zones names in each UTC offset:

Time Zone UTC Offset

Some higher latitude areas use daylight saving time for part of the year, often adding an hour to local time during spring and summer. For example, the state of California (USA) uses Pacific daylight saving time during the daylight saving time period with a UTC offset of UTC-7.

But Pacific Standard Time with an offset of UTC-8 for the rest of the year.

Time Zone Offsets

Time Zones Offsets

All time zones across the world are UTC plus or minus some time, usually one or more hours. Anything west of zero longitude will have a negative offset, and anything east will have a positive offset.

Eastern Standard Time, the Eastern Standard Time observed in the Americas, for example, is UTC-5, while Central Asian time will be UTC+5. For Eastern Standard Time, the time is 5 hours behind UTC time.

This UTC time zone difference is the UTC offset or time zone offsets. Each region of the Earth has its distance measured east or west of the prime meridian which is theoretically placed in Greenwich, London, UK.

The meridian also serves as a reference mark for Coordinated Universal Time with one hour for every 15 degrees of longitude. A specific longitude in degrees must be divided by 15 to determine the precise time zone in hours.

As the Earth rotates around its axis, it moves about 15 degrees every 60 minutes. After 24 hours, it has completed a full 360 degree rotation. Scientists used this information to divide the planet into 24 sections or time zone.

Each time zone is 15 degrees longitude.

Time Zones And Times:

Below is a list of the main time zone offsets worldwide in each UTC offset:

UTC Offset Current Time

To see the real-time time with seconds at each of the UTC offsets listed above, click on each one to be redirected to the official page for each offset. All time zones are defined as offsets from UTC, ranging from UTC-12:00 to UTC+14:00. UTC offsets are written in the format ±hh:mm, ±hhmm, or ±hh (hours ahead of or behind UTC).

The distance between the zones is greatest at the equator. It shrinks to zero at the poles because of the Earth's curvature. As the equator is about 24,902 miles long, the distance between time zone at the equator is approximately 1,038 miles.

Time Zones Half Hour:

UTC offsets are usually a whole number of hours, but some zones are offset by an additional 30 or 45 minutes, such as in India, South Australia, and Nepal.

Below is a list of the main time zones half hour worldwide in each UTC offset:

UTC Offset Current Time

To see the real-time time with seconds at each of the UTC offsets listed above, click on each one to be redirected to the official page for each offset. Because time zones are based on longitude segments and narrow longitude lines at the poles, scientists working at the north and south poles simply use UTC time.

Otherwise, Antarctica would be divided into 24 very thin time zone. With the growth of the Internet and global communication and commerce, some have advocated a new world time system. The first leap second was added on June 30, 1972.

In total, there have been 27 seconds added to UTC over the years, to date. The length of the mean solar day is increasing because the Earth's rotation speed is slowly decreasing due to the slowing effect of the tides.

The Earth will continue to slow down its rotation, so more and more leap seconds will be added in the future to compensate. There are proposals to replace UTC with another standard that does not use leap seconds to adjust the time after the atomic clock time.

Time Zones Definition

Time Zone Definition

Time zones have been set to determine noon across the world. Because of the Earth's rotation, noon arrives at different times in different places around the world. To control the climate around the planet, countries adhere to certain time zone.

Keeping the same amount of time is very useful for countries and people who do business together or who do all kinds of other activities together. However, the main time zone meaning can be understood in its wide variety of social, legal and commercial reasons.

Time zones are needed because people in different places experience the hour at different times of the day. Time zones also define and establish the appropriate time in individual countries and regions, having a huge impact on business, communication and management worldwide.

Check out our time zones wiki and learn more about it:

Why Time Zones Were Created?

People have lived in different time zones for a long time, but it wasn't always as organized as it is today. For millions of years, people have measured time using natural resources like the sun or moon. Both the ancients and the 18th century used to watch the sun every day to know what time it was.

Consequently, most people were well acquainted with nature and its wonders. Specifically, when the sun was highest in the sky, they knew it was noon. Before the end of the 19th century, timekeeping was a purely local phenomenon, towns and cities set their own time.

A person would make sure that the city's official clock indicated noon, when the sun was highest in the sky each day. The city clock would be the official time and citizens would adjust their pocket watches and clocks to the city time.

Enterprising citizens offered their services as mobile clock setting, carrying a clock with the exact time to adjust the clocks in customers' homes on a weekly basis. So they would walk around town and adjust other people's watches to make sure they matched.

However, the need to develop more accurate time calculation mechanisms became increasingly necessary. In the 19th century, as the world became more connected with improved transportation and telecommunications systems, it became increasingly inconvenient for each location to observe its own solar time.

Traveling between cities meant having to change your pocket watch on arrival. Especially when people started traveling around North America by train, the many time zones became difficult to follow because each stop was based on a different local time.

At one point, only train stations in the United States had to keep track of 75 time zones across the country. Standardization of time was essential for the efficient operation of railroads. Despite the need for a standardized time, people couldn't agree on it for a long time.

The first place of debate was England, where the railway community began its fight for general rules for all cities. They were the first to apply standard time within the country's boundaries. In November 1840, the Great Western Railway began using GMT maintained by portable chronometers.

This practice was soon followed by other railway companies in Britain and became known as Railway Time. The Railway Clearing House, the transport institution in Great Britain, accepted the Greenwich Meridian Time as universal within the entire country's railway system in 1847.

Around August 23, 1852, time signals were first transmitted by telegraph from the Royal Observatory. By 1855, 98% of Britain's public clocks were using GMT, but the island's legal time was not made until 2 August 1880.

Some British watches from this period have two minute hands, one for local time and one for GMT.

The time zones history is very entertaining and intriguing.

Who Invented Time Zones?

There was a lot of controversy about who created time zones. Italian mathematician Quirico Filopanti introduced the idea of ​​a world system of time zones in his book Miranda!, published in 1858. He proposed 24-hour time zones, which he called "longitudinal days", the first centered on the meridian of Rome.

He also proposed a universal time to be used in astronomy and telegraphy. However, his book did not attract attention until long after his death. In 1878, a lost train in Ireland by Sandford Fleming led to the invention of world time zones.

Fleming was one of the leaders in the effort to develop a worldwide weather control system and presented his invention at several international conferences. He recommended that the world be divided into twenty-four time zones, each spaced 15 degrees longitude.

As the Earth rotates once every 24 hours and there are 360 ​​degrees of longitude, every hour the Earth rotates one-twentieth of a circle or 15 degrees of longitude. Sir Fleming's time zone were heralded as a brilliant solution to a chaotic problem across the world.

In 1883, railroad companies in the United States began using Fleming time zones. In 1884, an International Prime Meridian Conference was held in Washington D.C. to standardize the time and select the prime meridian.

The conference selected Greenwich, England longitude as zero degrees of longitude and established the 24 time zones based on the prime meridian. While time zones were established, not all countries changed immediately.

Although most US states began adhering to Pacific, Mountain, Central, and Eastern time zones in 1895, Congress did not mandate the use of these time zones until the Standard Time Act of 1918. On January 1, 1960, Coordinated Universal Time (UTC), the international basis for civil and scientific time, was introduced.

Where Do Time Zones Start?

Most time zones explained are exactly one hour apart and, by convention, calculate their local time as an offset from UTC or GMT.

All clock changes around the world are automatically considered and displayed in real time as soon as you reload the page.

Both cell phones and computers adjust the time automatically when you travel from one time zone to another.

But you will have to manually adjust your clock.

Where Time Zones Change?

Born as a wartime energy conservation measure, the adoption of daylight saving time is inherently political and its abolition equally political. Most tropical countries see absolutely no need for daylight saving time, sticking to standard time all year round.

Sometimes a subnational jurisdiction (such as Saskatchewan or Arizona) politically chooses not to use daylight saving time. During daylight saving time, the time zone name and time change. The words “daylight” or “summer” are usually included in the name, and the local time is usually advanced by 1 hour.

In the United States, daylight saving time begins at 2:00 am on the second Sunday in March and ends at 2:00 am on the first Sunday in November. Two states do not observe daylight saving time, Arizona and Hawaii.

There is no universally agreed point of the year to switch from standard time to daylight saving time, leaving wild jumps and fluctuations where one country has already changed and the other has not.

Are Time Zones Capitalized?

Today's technologies allow us to move from one time zone to another in a matter of a few hours. And this system is very complicated and requires proper regulation that helps to avoid any confusion or possible error caused by misinterpretation.

Flights from east to west, where you get a few hours, are usually a little easier, as most people find it easier to stay up a little later than to go to bed earlier. A general rule of thumb is that you recover about 1 hour of difference per day.

You may find that when you leave you are fine after just a few days, but you will really notice the recovery period on the way home. At this point, your biological clock will be really messed up and it will take a while to sort things out.

If you're landing early in the day, try sleeping on the plane so you arrive refreshed and ready for a full day of activities. You can help the process a little bit by trying to operate in your new local time as early as possible and spending the daylight hours in your new time zone outdoors for the first few days.

Which Organizations Regulate Time Zones?

Time zones obey specific rules regarding geographic principles of longitude. The International Earth Rotation and Reference Systems Service (IERS) is the institution responsible for maintaining global time and reference frame standards, notably through its Earth Orientation Parameter (EOP) and International Celestial Reference System (ICRS) groups.

ISO 8601 is a standard established by the International Organization for Standardization that defines methods of representing dates and times in textual form, including specifications for representing time zones.

The Department of Transportation (DOT) takes an important part in timekeeping as well, by regulating it and establishing standards to follow. This coordinated time scale is maintained by the Bureau International des Poids et Mesures (BIPM).

The BIPM is an international organization established by the Metre Convention, through which all the Standards related to the time measuring are discussed and implemented on the worldwide level. The United States of America is provided with services of timekeeping by two federal agencies: The National Institute of Standards and Technology (NIST) and the United States Naval Observatory (USNO).

These organizations make sure to keep the clocks synchronized and the time updated.

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