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Time Zones in the World: Why Do Countries Change Their Time Zones?


If you look at the clock and ask someone from another side of the world what time it is, you'll notice that there’s a big difference. It is indeed remarkable how people live on the same planet but experiences different times. It could be a day in your area while it is still night in other countries. Have you ever wondered what causes the difference in time zones? There are different time zones in the world, and some countries change clocks in a certain period. Find out why some countries and states change their time zones.


Earth’s Rotation and the Time Zones in the World

You have learned in your science class that the Earth rotates. It completes a full rotation every 24 hours. As the planet rotates, some places receive sunlight or darkness, resulting in day and night. As the Earth rotates into the sunlight, you’ll see the sunrise, whereas rotating out of the sunlight is where you see the sunset.

The Earth’s rotation is the primary cause why countries follow different time zones. Without it, noontime will be morning or even evening in other places. Many time zones were created before, confusing travelers about the time. In the 1800s, scientists used a new system for time zones based on the degrees of rotation and longitude. As a result, they have created the standard time to divide the Earth into 24 sections or time zones. 

Every time zone is 15 degrees of longitude wide. The prime meridian refers to the longitude’s primary dividing line. On the other hand, longitude refers to the angular distance between a point on any meridian and the prime meridian at Greenwich. This place is a suburb in London where the imaginary dividing lines begin. Greenwich Mean Time (GMT) is the time zone followed in Greenwich. As you move to the west, the time zone becomes one hour earlier. When you move to the east, the time zone becomes an hour later.

Why Do Countries Change Their Time Zones?

If all countries follow the standard time, there will only be 24 official timezones. However, some countries like China did not accept the idea of standard time right away. They continue to use their times until today. For instance, China follows only one time zone instead of three standard time zones. Other nations only adopted the systems using smaller increments like 15-30 minutes instead of one hour. Since some countries did not follow the standard time, additional time zones were created. As a result, there are more time zones that nations and states follow. 

Spring Forward, Fall Back

There's another reason why some countries and states follow a different time zone. It is called Daylight Saving Time. Although it is not a time zone, DST requires some countries and states to set the clock one hour forward or one hour backward from the standard time. But why is there Daylight Saving Time? Why do countries follow it?

Daylight Saving Time is followed to make better use of the light. For instance, if a place moves the clock backward an hour in the autumn, people can effectively transfer an hour of daylight from evening to morning. As a result, they can be more productive. The opposite thing happens in the spring. DST is an effective way to have an extra hour of daylight in the evening.

Although the intention of using Daylight Saving Time is good, adverse effects still arise. People who are not used to DST can have trouble with their circadian rhythm. When the body clock is disturbed, it can lead to sleep problems. As a result, there is an increase in the risks of heart diseases and other health conditions. To minimize the effects of DST, individuals living in countries that follow DST should live a healthy lifestyle. Getting enough sleep is one way to prevent any serious health condition. 

Standard Time and Daylight Saving Time

Some countries follow the standard time only. Some countries that do not follow Daylight Saving Time live in the Winter Time Zones (Standard Time Zone). Among the most popular countries which do not observe DST are the following:

  • China
  • Japan
  • The United Arab Emirates
  • North Korea
  • South Korea
  • Argentina
  • Most recently, Brazil (since 2019)
  • Tunisia (since 2009)

On the other hand, some countries considered not to switch their clocks again. However, they have implemented a Standard Time Zone wherein they opted to stay on summer hours all year round. Among the countries/states/provinces that observe this type of measure is the following:

  • Argentina
  • Belarus
  • Iceland
  • Kyrgyzstan
  • Malaysia
  • Morocco3
  • Namibia
  • Russia
  • Saskatchewan
  • Singapore
  • Turkey
  • Turkmenistan
  • Uzbekistan
  • Yukon

Other countries use both Standard Time Zone and Daylight Saving Time during specific periods of the year. If you like to travel, knowing the time zones you will visit can help you make plans and set appointments.

The world has more than 24 time zones, making it hard for you to determine the accurate time in different places. But with the standard time, you can use the system to know what time it is to the other parts of the world. However, you need to consider whether those locations use the standard time because other countries observe Daylight Saving Time, and others have their time zones.

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