How May Time Zones Are There in the World?

NASA Goddard Space Flight Center/CC-BY 2.0

There are 24 different time zones in the world set at 15 degree longitude intervals in between. The Earth completes one full rotation in 24 hours at a speed of 15 degrees per hour. The premise behind time zones is that the world is theoretically divided into 24 equal longitudinal zones and the time is accordingly adjusted in each zone by an hour.