World Time Zones
Here are the time zones of the world. All places in one time zone have the same time, except when a region has "Daylight Saving Time" when the local time is advanced by one hour. On this map there is no adjustment for Daylight Saving Time!
Why Different Times?
Because when the Sun is high in the sky in one part of the world, it is night-time in another place.
So for "Midday" to be close to the middle of the day, the world has to be divided into different time zones.
Why does the Sun Rise and Set at Different Times?
We have a special page that explains this here: Earth's Orbit and Daylight.