Why time zones?

Noon - Derived from the Latin word for ninth. The word "noon" originally meant the ninth hour after sunrise, or 3:00 p.m.--generally the hottest part of the day and the time when most people in the Roman Empire would break for lunch.

In the twelth century it started to shift in meaning from 3:00 (9th hour) to mid-day when time of Church prayers shifted from ninth hour to sixth hour, or perhaps because the customary time of the midday meal shifted, or both. The shift was complete by the 14 century.

 

Was that based on a 24-hour day?

 

They started counting the hours at sunrise, which is why the 9th hour was 3:00pm (approximately)

from;
Roman Time Keeping

 

4:20 is high noon...

 

Time zone's are antiquated in the 21st century. One standard time for the planet I say. To be neutral. At 12:00 am in the dead center of the Pacific tomorrow morning, we all call it 0:00.

Then we start using 24 hour days.