How many time zones will be crossed when you travel from Colorado to China?

Traveling from Colorado to China, you would cross over 14 time zones.

There are 4 main time zones in the United States: Pacific Time, Mountain Time, Central Time, and Eastern Time. So, if you start your journey from Colorado (which lies in the Mountain Time Zone, UTC−07:00), you would encounter 4 time zones to reach the easternmost point of the United States (UTC−04:00).

Then, crossing the Pacific Ocean, you would essentially go back in time by 20 hours, as most of China falls within the China Standard Time (CST, UTC+08:00). When you arrive in China, you would have thus crossed a total of 14 time zones.