You’re never gonna convince the world to remove time zones. Switch to UTC and now the idea of the sun rising between 5-7 AMish is ruined because it would be 2 AM where I am now. Since the invention of the sundial, time zones have existed in some form or another. Programmers just have deal with it.

The sun doesn't rise between 5-7 AM-ish in many parts of the world.

First, if you timezone is 'right', on average the sun should rise about 6 am. In winter, it rises later, in summer it rises earlier.

Where I grew up in Germany the sun rose as late as 8:20 am in winter. And funny enough, the latest rise in Madrid in Spain is at 8:40 am in winter. That's because Madrid is on the 'wrong' timezone: it's in the same timezone as Germany, but much further west.

(You are right however, that time zones do roughly keep noon around 12-ish. It's just that the band of variation around the world is quite a lot wider than you might imagine.)

> Switch to UTC and now the idea of the sun rising between 5-7 AMish is ruined

And this idea is critically important because?

It alone isn’t. But the notion of the sun rising in the mid-AM, midday being at noon, and the sun then setting in the mid-PM is literally as old as the sundial. There’s no way you’re convincing society that “no timezones” is a good thing.

That idea has some quite surprising and arguably inconvenient consequences: https://qntm.org/abolish

Most notably, the concepts of "today" and "tomorrow" stop making sense!

More to the point, you cease to be able to predict what people many miles away from you are doing:

It's 6 AM in London. What time is it in Denver?

The way things work now, it's approximately midnight in Denver, or close enough that the safe answer to the question "What is my business partner in Denver doing?" is "Sleeping" which neatly answers the question of what their likely response will be were I to call them now.

Now, imagine we abolish time zones:

It's 6 AM in London. What time is it in Denver?

It's 6 AM. It's 6 AM in Beijing, in Cairo, in Honolulu, at McMurdo Station, and in Sidney, Montana. I have little idea what anyone in Denver is doing, unless I happen to know that Denver is placed such that their dawn is six-ish hours after mine. But I have no way to express that conveniently, and nobody else thinks in those terms, so I can't build up a database of such information.

At least, not without reinventing something...

It's 6 AM in London. What time is it in Denver?

What would I be...

It's 6 AM in London.

Something occurs...

The clock is striking thirteen.

I almost...

DENHAM'S DENTIFRICE!

Consider the lilies of tzdata...

DENHAM'S...

Sorry, got a bit caught up there.

> It's 6 AM in London. What time is it in Denver?

> The way things work now, it's approximately midnight in Denver, or close enough that the safe answer to the question "What is my business partner in Denver doing?" is "Sleeping" which neatly answers the question of what their likely response will be were I to call them now.

Memorizing a timezone offset is basically still what you'd need to do. To know that it's approximately midnight in Denver, you have to have that memorized or look it up.

Once you have that 6 hour number, in a single-timezone world, you'd simply say "ok what were people here doing 6 hours ago?" and you'd have your same answer.

Of course people would still publish those sorts of "conversion tables"/offsets, because people would still have that exact problem! But they'd possibly be a bit more precise than historically - with current computer tech, it might actually be more accurate, e.g. using actual GPS coords instead of broad swaths, so it would be like "Denver is 6.24 (or whatever) hours behind your current location." Let alone how much better that might work for cities in single-timezone China, say.

(I'm personally against this idea, anyway, but that particular argument has never satisfied me.)

> Of course people would still publish those sorts of "conversion tables"/offsets, because people would still have that exact problem! But they'd possibly be a bit more precise than historically - with current computer tech, it might actually be more accurate, e.g. using actual GPS coords instead of broad swaths, so it would be like "Denver is 6.24 (or whatever) hours behind your current location." Let alone how much better that might work for cities in single-timezone China, say.

This is keeping (a rationalized version of) time zones in every respect except for how people set their clocks.

In the system you propose, people would operate at the equivalent of 9 AM to 5 PM, except you expect that they'd quote different times (even with fractional hours) to maintain the façade that time zones no longer exist. A business no longer operates nine to five, it's 1:15 PM to 9:15 PM, and people can't just say "Oh, Denver is six hours behind London right now" because Denver isn't exactly ninety degrees west of London.

Ironically, aside from everyone around the world setting their clocks to the same time, that's how time worked prior to the introduction of time zones, so I can't fault you for coming up with that idea.

They already don't make sense when you're trying to coordinate communication with people more than a few timezones away

If we abolished time zones, it wouldn't make sense /ever/ for people in some parts of the world, even when communicating with people close to them. That's worse.

That's already the case for people very far North/South. Summer/winter become their own day/night at the poles... according to the Sun. If you take a walk around the pole, you can cross several timezones and end back where you started while having "lost an hour" every few steps. Of course, in one of those crossings you "gain a day" so, watch your step!

Why wouldn't it make sense "ever" in any part of the world?

In some areas, standard workdays would span "days". So e.g. a business would need to post its hours as "M-F, 00:00 - 1:00, 17:00 - 24:00". (actually it's even worse as the last 00:00 - 1:00 is on a Saturday)

Or imagine chatting with a friend at 23:00 about plans after you get off work at 1:00 the following "day". "See you tomorrow?"

Or do you reserve "tomorrow" for telling someone at 8:00 that you'll get back to them when you wake up at 16:00 that same "day"?

Today people only have to deal with this when communicating with people many time zones away, but now it's an issue even within a single area!

Which defeats one of the supposed “benefits”: “meeting at 2PM” means the same everywhere.

"Meeting at X" means exactly what it always meant. The only difference made by removing timezones is that you don't need to adjust the time for remote dial-ins. 2PM becomes 2PM everywhere.

Right, UTC all of the things!

A reasonable idea, for people living in Europe or Africa.

Also works for people in New Zealand; they just use a 12-hour clock and flip AM and PM.

And stop using the notions of „today“ and „tomorrow“?

Having the date change at lunchtime would be really confusing.

Maybe. Though eg the Jewish calendar changes dates at sunset as far as I can tell, and that seems to work just fine?