[codex]

UTC everywhere simply moves the complexity somewhere else. You still need time zones to know when the locals get up and go to sleep. My flight gets into Fiji at 22:07? Is that morning or night? Will they be serving breakfast during my layover in Istanbul? When should I schedule my conference call with Tokyo?

[pbiggar]

Morning or night isn't important, you probably want a slightly different question: is public transit still running, can I get a bite to eat, will it be dark, when should I go to bed? Those are questions the local time approximates very crudely, and we wont need tom implement a DST equivalent because it wont help.

In Istanbul, they go to clubs late at night, not early like in Dublin. In Italy, nobody is in the sun at noon. In San Francisco, many of the locals start work around noon. In Spain they siesta. In Japan, they have 12 hour work days. In India, some people work US schedules. In Finland in high summer, its not unusual to see kids out late into the "night", as the sun never goes down.

None of this is accounted for by DST or local times, and you always need to augment your time information with local understanding.

[riffraff]

> Morning or night isn't important

actually morning or night encodes most of the things.

For example, when visiting city X I won't check whether public transport is running from/to the airport if I know I'm arriving at 11:45, as I can safely assume it's there, while I will if I am arriving at 23:45 I'll have to find out whether public transport is running, or if there is taxi service I can pay with my currency, or if there is an exchange office open that late etc.

Of course you may need to check some specifics, but other than borderline cases you may assume with reasonable confidence that if you visit turkey, ireland, italy, USA, spain, finland and japan _in the morning_ you will be able to visit a city with daylight, use public transport, exchange your money, eat out.

[zanny]

You are just moving complexity though, and transitioning to UTC globally eliminates broad classes of unneeded communication overhead. Right now, while you can assume at 11:30 AM public transportation is available, you have to look up what actual time zone wherever you are going is in and do math to figure out when that is for you. If everything were UTC, you would just look up the average operating hours of the day in whatever region you were looking at, and would just get a number like "This city operates from 4:00 to 16:00" or from 12:00 to 24:00."

I'm also going to argue that we are rapidly adapting our schedules to more broadly match regions around us rather than just following the sun. Business hours and school hours have been shifting later in the day in the US, and I have a feeling a large part of that is due to more constant contact with Europe being hours ahead. The majority of people don't know or feel the subtle tug of the global community towards a unified activity time block, but I think it is happening.

[riffraff]

> You are just moving complexity though

changing to UTC everywhere is moving complexity, I stand by the "keep the complexity where we have it already" :)

> Right now, while you can assume at 11:30 AM public transportation is available, you have to look up what actual time zone wherever you are going is in and do math to figure out when that is for you.

well, no. If I book a flight/bus/train it says that I get somewhere at 11:45 local time, they don't give me zulu time.

But assuming they'd tell me the hours in _my_ time, the complexity of doing a 2 digit sum is, IMVHO, not a major complexity over looking up what the time zone is (or equivalently, what the "beginning of the day" is locally).

It is possible that we are undergoing a shift towards more unified time. But for what is worth, I can tell you that the time shift in Italy over the last twenty years has been in the same direction as yours (e.g. TV prime time used to be 20:00, then 20:30, now it's 21:00), so maybe europe's being pulled from east asia being pulled from americas being pulled from europe ad infinitum.

[zanny]

> changing to UTC everywhere is moving complexity, I stand by the "keep the complexity where we have it already" :)

Like I said, it eliminates the class of complexity that matters. Scheduling appointments and synchronizing people across time zones, something more common today, and will become more common forever into the future, and will become absurd once we have regular space travel, is a much larger cost set than when people move across what are currently time zones permanently, and need to adapt to getting up or doing things at different numerical times habitually.

> well, no. ..... so maybe europe's being pulled from east asia being pulled from americas being pulled from europe ad infinitum.

They won't tell you the hours in your time, and if they do, they are doing time zone conversion math already. Right off the bat, you have undue overhead in communicating time. The question is that people would be used to having the "day" be between a certain set of hours in one place, and then by migrating across what was a zone boundary what they would expect is now an hour off from their internal clock, because most people still behave in some synchrony with the sun.

1. You won't avoid someones internal clock being off by moving into an area of different daylight hours. To note, time zones only make the number match by longitude as well, latitudinally crossing the equator or going extreme distances north or south produces the same effect (different areas have different patterns of awakeness based on the availably of the sun) so that will already offset regular operating hours of various things, just moving north or south. Using UTC universally makes that concept ubiquitous as well, rather than having the disparity that moving east or west "changes' the time, but going north or south doesn't, but going anywhere societies change the operating schedules.

Like I said, I think it is much easier on anyone considering business to have a unified time standard, and accept that the hours of public services and resources will be different wherever they go, instead of converting time across zones for purposes of communication or meetings.

[henrikschroder]

> Business hours and school hours have been shifting later in the day in the US, and I have a feeling a large part of that is due to more constant contact with Europe being hours ahead.

For the US to get more of its workday in contact with the European workday, it would have to shift it earlier in the day, which is the exact opposite of what you're saying.