A time zone is a region that uses the same standard time. Time zones help people coordinate clocks, schedules, travel, business hours, and communication across different places.
Why time zones exist
Earth rotates, so noon arrives at different places at different times. Time zones divide the world into regions where clocks can be set in an organized way instead of every town using its own solar time.
Time zones and daylight saving time
Some places also use daylight saving time, which shifts clocks during part of the year. Not every country or region uses it.
Time zones are a human system built around Earth's rotation and practical scheduling.