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What is the need for different TIME ZONES?

Look at the above four clocks of different nations. Why does it show a different time?

In this blog post, we are going to look into the aspects which enforced this 'different time zones' concept into work!

Hurry up! Go to the nearest clock. What time is it where you are? Have you traveled to different countries and experienced a time change. Is it time travel? Of course not! That is just because of different time zone.

NEED; Why it is required?

To understand time zones, start by thinking about the shape of the Earth. You already know, our planet Earth is round in shape and takes a complete turn around itself in 24 hours.

Now imagine shining a flashlight on the globe. One part of it will receive light and the other would remain dark. So, as Earth rotates, different parts of it receive sunlight or darkness, giving us day and night.

Imagine, if the entire Earth had a single time zone. Noon would be the middle of the day in some places and others would experience night, evening, or morning. Since different parts of the earth have daylight and night at different times, in the same way we require different time zones.


People have lived in different time zones for a very long time. However, it hasn't been as organized as it is today. Just a century ago, people use to keep their own time for their place. The official of that place made sure that the clock should read noon when the sun is at the highest in the sky each day. Then, they would go to town to match the time in other people's clock. It was chaos.

As the population increased, it became more complicated. Especially the people traveling through train faced difficulties keeping up with different time zones which were kept unofficially. The need for standardization of time increased year by year.


In the late 19th century, few scientists came up with a new system of time zones; which was standard time. They started by building a time zone map by studying the movement of the earth.

The earth rotates 15 degrees every 60 minutes. Scientists used this information to plan the map of time zones. Finally, they divided the earth into 24 time zones.

So, the distance between the zones was the greatest at the equator and becomes zero at the poles. The equators stretch about 24902 miles long. So the distance between each timezone at the equator is about 1038 miles.

Before we move further, just a brief about longitude and latitude:

Longitude lines run north to south and latitude lines run east to west.

Now, the starting point of these timezones was the prime meridian. The prime meridian is the primary dividing line of longitude. It also passes through Greenwich, a suburb in London.


Therefore the time at Greenwich was known as GMT (Greenwich Mean Time). GMT may sound familiar and today you may have learned why it is said like that :)


-> As you move 15 degrees westward of Greenwich, you would be 1 hour earlier.

It is presented as GMT -1

-> Likewise, as you move 15 degrees eastward of Greenwich, you would be 1 hour later.

It is represented as GMT +1

However, not everyone accepted this, and therefore there are some other time zones apart from these official 24 time zones.

Having different time zones 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.

Let’s take a closer look at how this works.

Suppose that you live in Delhi, India which is five and a half time zones east of Greenwich. That is GMT + 5:30. Your cousin lives in Charlotte, North Carolina which is five zones west of Greenwich. So, Madrid is GMT - 5.