Time zones
Why does China have one time zone?
China spans several ideal longitude bands but uses one official national clock: China Standard Time, UTC+8.
One official clock across a wide country
China officially uses China Standard Time, also known as Beijing Time, at UTC+8. Government schedules, transport and other official timetables use that same civil time across the country.
Solar noon does not have to be noon on the clock
A single national clock means the Sun reaches its daily high point at different civil times across the country. That is not an error in the clock; it is the trade-off made when one administrative standard is used across a broad range of longitudes.
Use a zone identifier, not an abbreviation
CST is especially risky shorthand because it can mean China Standard Time, Central Standard Time or Cuba Standard Time depending on context. For a meeting, say China Standard Time or use Asia/Shanghai, then include the date.