There are 24 different time zones around the world.

Cities in different time zones have different times.

24

There are a total of 41 different time offsets used around the world every year, and they have 161 different names.

Because it is in a different time zones (three time zones away). As you travel around the world, the sun comes up at different times (In the US, you see it sooner the farther east you are), and so there are lines set up throughout the world that make up time zones, so that people where the sun isn't up yet don't have to try to live on the same time schedule as someone around the world where it is already night.

At any given time, the clocks around the world are set to at least 38 different times, and these time zones have about 165 different names, including about 130 different names just for Standard Time designations.