I believe no one else mentioned this but... China is a case study of why this is a terrible idea

The entire PRC uses the same time zone, even though in any other parts of the world, China should have been split to at least 3 different timezones

It is very disorienting to try and go for breakfast in Tibet at 9 am to find that nothing is open and the sun is just out... So yeah. Imagine if this is extended to 12-hr differences

Wikipedia has a nice summary of this

Because we like midnight to happen at night, and noon to happen during the day

That would make time more unrelated to the sun, which is pretty important.

Because that would be a nightmare. "I'll meet you for lunch at 2AM", "No, I had a huge breakfast yesterday". You would need to relearn the times every time you went to a different place, "oh, right, the restaurants only serve lunch until 10AM" or "Sorry sir, but there's an extra fee for night time services starting 1PM". Those are much more likely day-to-day phrases than scheduling a meeting with someone from another continent. And you don't gain anything by this, because whenever you're communicating across timezones you can simply use UTC as a standard and everyone knows how to convert that to their own time. So there's no good reason and a lot of drawbacks.

So you want to abolish time zones.

The cultural relationship with time is more important than its absolute measurement.

Because "the markets open at 9" is an international standard that everyone can count on. You could stagger it so that one country's market opens at 10, then another at 12, and so on, but then what if one country chooses a different standard? What if a restaurant picks a different convention than businesses in one area? Time zones are great because once you understand them, you'll always know how time works locally, anywhere in the world with a single piece of information, it's a truly successful standard.

This is a surprisingly divisive topic every time I see it or suggest it. I reckon the divisor is "people who use and work across timezones a lot" and "people who don't". Fuck I hate timezones.

because we sleep at night and are active during the day, and so we need to track that in a way that is universal. if i mention 12:00, people understand that it is noon where i am, and if i mention 22:00, they know it's bedtime.

the whole point of time zones is to have time cohesion in a wider region within margin of error, so people on the far east and far west of a time zone are close enough to solar noon at 12:00. you can take a train to a neighbouring city without having to worry about needing to adjust your timekeeping devices by a few minutes.

to put your scenario into perspective, china has already done what you suggested on a smaller scale: the entire country is on UTC+8 for the sake of "unity" and "national cohesion". beijing loves it; 12:00 is still noon there! except it ain't in xinjiang and tibet. xinjiang has its own unofficial xinjiang time zone of UTC+6, and so people have to specify which time zone they're talking about and convert times between the two time zones in conversation because the uyghers use xinjiang time and the han chinese use beijing time, and you can imagine the confusion and also technical issues that has arisen from that.

imagine that, but 12 times worse. no thanks, i'll do the simple math of converting time zones if i ever need to communicate internationally.

fuck daylight savings. take that shit out back.

We should also all work 9am-5pm of course.

Edit: it would be wild because in the USA the shops would open in the middle of the night etc.

On the other hand, we could refine time zones so they’re continuous instead of discrete chunks. Then every step you take adjusts the time. Would be more “accurate.”

That would be shifting from timezone to "workzone" or "noonzone". At this moment you need to setup a meeting with people, then you ask which is their timezone. With global UTC timezone, then you need to ask, which are your work hours? (workzone).

It would make it even harder for people to understand when it was in a different timezone. Right now I know that 11pm is late for anyone on thier own timezone. But with no timezone, I would say, the meeting is at 23:00. Thats mid morning for me, what is that for you... the answer is way less exact, and harder to covert.
So you day is my day minus half a morning?

I see this argument all the time. Forget all the tradition, "people like noon near solar noon", all that.

Date changes mid day some places and not others would be a nightmare for so many things.

What're you doing on the Tuesday half of June 15/16th?

Almost a century ago, the fascist dictator of Spain wanted to appease Hitler and decided to move the timezone from the UK one to the German one. With daylight savings the situation in summer was a bit ridiculous: dark until 9 am and sun until 10 pm, it was very confusing as a tourist to have all the stores to open so late in morning and go out to eat dinner so late

I can't imagine what kind of mess would be going to Japan as a tourist on UTC+0

Here are some reasons told through what-if.

TL;DR: People like to sleep in the dark generally, and businesses that close are open when more people are awake.

Maybe it would be easier if the earth would be flat :)

Long discussion here. I feel I'd like to add two things. First: we already do. If you coordinate international video calls or conference live streams, you'll say it starts 14:00 UTC. That is something we can do and regularly do. Some companies will use the timezone of their headquarters, though.

Furthermore: Once you're already in the process of changing how time works, don't do a half-assed job. Go all the way and make it metric. Do away with all the 12/24 and 60s. And make things divisible by 1000.

Why should the UK get to be the only place with an accurate local time? I don't want to live on UK time.

So if I'm in Vancouver BC it would go from Friday to Saturday in the mid afternoon? Is Friday night the first night of the weekend or the last night of the work week?