All of China runs on Beijing time despite having 5 time zones: Here’s why 

China is the third largest country on the Earth and is roughly the same size as the US or Canada. Yet, it uses a single time zone against six time zones followed in the US and Canada? That means in all of China, which spans through almost 4800 kilometres, people follow the same clock despite the sun rising and setting at different times in different zones.  

So, if you are in the far east side of China and the sun rises at say 6 am for you, it does not rise until 10 am for your friend who is in the west. The same goes for sunset, too.  Weird, right? Let us understand why this is so.  

Time Zones 
First things first. How do time zones work? A time zone is a region in which the same standard time is followed. If you look at the world map, it is divided into 24 time zones. Each of these zones spans 15 degrees in longitude and differs by 1 hour from its neighbouring time zone. The time in each of these time zones is conventionally defined by its offset from the Coordinated Universal Time (UTC) and the UTC is based on the prime meridian (that is 0 degrees longitude).   

Accordingly, UTC+1 refers to 15 degrees east, UTC+2 to 30 degrees east, and so on. In all these ideal time zones, the sun is at its highest in the sky (solar noon) at around noon i.e 12 o’clock. Most countries in the world observe a standard time that is as close as possible to their ideal time zone to ensure that solar noon occurs around noon. 

China: 5 Time Zones in 1 
China covers more than 60 degrees of longitude. That is 5 geographical time zones with UTC offsets ranging from UTC+5 to UTC+9. But as we told you, all of China observes the same time zone, which is UTC+8. This time zone is internationally called China Standard Time (CST) while locally it is known as the Beijing Time Zone.  

The Beijing time Zone  
Given the huge geographical dimensions of China's single time zone, solar noon occurs at different times across China. It occurs much later than 12 o'clock in the country's westernmost areas. In a place like Kashgar, in western Xinjiang, solar noon can be as late as 3:10 pm while in the eastern areas, solar noon is before 12 o'clock. For example, in Fushun, the year's earliest time of solar noon is 11:27 am. In comparison, in Beijing, solar noon is very close to 12 o'clock, between 11:58 am and 12:28 pm.  

But the situation was not always like this. From 1912 until 1949, China did have 5 time zones set according to the ideal time zones. But in 1949, the then Communist Party Chairman, Mao Zedong decided that all of China was to use Beijing Time. Since then, China’s clock has been working according to the Beijing time.