Although comparable in land mass to the US and spreading east to west in what might be otherwise construed as 5 separate time zones, the standard of Beijing Time (UTC+8:00) extends the whole of China!
This can be both convenient and confusing.
A local man in Urumqi, capital of Xinjiang, China. At what time does he drink his first morning tea?
On one hand, communicating with people around China or planning a trip with multiple stops becomes really simple. If you can figure out the time in Beijing, you'll know the local time anywhere in the country.
On the other hand, as you travel further west toward Xinjiang, the sun rises and sets at a remarkably later time in the day.
To put that into perspective, imagine you live in New York while your friend lives in LA. It's December as I write this, so imagine getting up and enjoying your breakfast to start your day promptly - the sun has just risen - you call your LA friend who is also getting up to have breakfast and start their day...
The sun won't rise for another few hours local to your friend in LA, they'll eat breakfast and go to work in the dark!
This has led to a sort of unofficial Xinjiang Time or Urumqi Time among locals of different cultural groups and much confusion, with the unofficial time about 2-hours behind Beijing Time, matching that of Kazakhstan at UTC+6:00.