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Comment by halfway | Hacker News Reader

Perhaps missing something obvious, but what's the advantage of having time zones over everyone using UTC/GMT?

As an example: I got up at 1 am today.

I bet you're able to understand that time point without me supplying the location. Weirdly enough, this advantage is more pronounced in the age of globalization.

Coordinating or planning things involving places whose longitudes differ by more than about 15 degrees generally requires taking into account that longitude difference.

Right now, we do that via time zones. If we went to universal UTC we'd still need to be aware of and deal with those longitude differences. It would still be convenient to quantize those differences into multiples of 15 degrees...and so we still end up with zones.

We could call them "space zones" or "longitude zones" instead of "time zones", but since the main purpose is to let you figure out what time on your clock corresponds to events like sunrise in other locations, we might as well continue to call them "time zones".

Because it's weird for planning purposes. I'd be eating breakfast in a "morning" hour in one country while someone else eats breakfast at a "night" hour somewhere else. Just kinda goes against the grain.

Maybe, but breakfast, lunch, dinner, and the many other tweens and variations are really just different words to describe meals. So let’s axe the distinction between them and simply call them “meals”.

A link above explains. You want to call your uncle in Australia. Is he awake? (home from work?, etc). You can't tell because it's the same "time" here and there but a very different part of his day.

To deduce whether your Australian uncle is likely at work, as an example, you need to know A) his work schedule and B) the difference in time between his and your locations.

If you’re both in the time zone, you need to know A) his work schedule. The idea that a person’s workday might be 1 AM - 9 AM might be difficult to comprehend, but only relative to our current understanding.

Predictability for travellers. It's helpful that no matter where you are, one has a relatively stable point of temporal reference to sunrise and sunset.

This map throws predictably out the window, rather violently.

Most of these states are motivated by ridding themselves of DST. Shifting time zones is just a byproduct here.

The benefit of time zones (that roughy correlate to local solar time) is that I can get a good idea about their day without any other info; (1am they're probably sleeping, 12pm they're probably at work but might take lunch). If I need to convert between time zones I use my handy lookup table that any computer/phone or back of the envelope math can do. If I want to have a meeting at 1pm in some new fancy Internet Time I have to do some gymnastics to figure out if my friends in India are even awake, let alone working. If I'm flying to Japan and my flight lands at 6am Internet time--should I find my hotel to sleep or go watch the sun rise?

You skipped that day at school when they tell you that Earth is round? :)

Also: how would you feel about starting your shift at work at 4:00 AM? because in UTC that's already 9:00 AM :) (assuming you're on east coast. On west coast your working hours would be 1:00 AM - 9:00 AM)

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