# Decimal Time Zones

:: Time

By: John Clements

What? There are no decimal time zones?

Okay, backing up.

I love time-wasting hard-to-learn idiosyncrasies. I use the dvorak keyboard, I run in sandals I make myself, I run my own mail server (surely the stupidest of my habits).

About two years ago I “invented” decimal time. Which is to say: I did in fact think of it myself. Unfortunately, there’s a bit of prior art here, going back to the French Revolution.

Short version: Our current day has 86,400 seconds in it. This is not really very far from 100,000. So… what if we just designated a decimal second as being 1/100,000 of a day? then we could have all of our hours and minutes be decimal divisions. More specifically: the day is divided into 10 decimal hours, each hour into 100 decimal minutes, and each minute into 100 decimal seconds. Works great! The decimal hours are quite long, but the decimal minutes are pretty close to our existing ones.

For reasons that escape me, people all over the world failed to immediately switch to decimal time. Actually, decimal time still crops up all the time when people add decimal digits to julian dates.

So. I’m still waiting. While I was waiting, I wrote a bit of JavaScript to display the decimal time:

GO JS

YAY JAVASCRIPT!

But there’s a problem. What should the time zones be?

About fifteen years ago, Swatch came up with this idea of having decimal time but of dumping time zones, so we would all coordinate on global time. Since then, many people have described one of the virtues of decimal time as being the lack of time zones. I don’t agree with this at all; I like time zones. I like the fact that if I fly to New York, the sun will rise at approximately the same “time” that it did in San Luis Obispo.

Our existing time zones, though, are pretty inextricably linked to our twenty-four hour clock—they divide the earth into twenty-four regions, after all. While it’s true that you can just use the existing divisions, it makes changing time zones extremely awkward. It’s easy to do the math—the day is 10 decimal hours, so dividing it by 24 leaves you with 0.0416666… Or, put differently, 0:41:67. That’s not a nice amount to have to move your watch by, or to try to translate in your head.

Surely there must be an existing definition of decimal time zones?

Bizarrely, it seems that there’s not a searchable, agreed-upon definition of decimal time zones.

So… I’ll make one up!

While it’s true that I hardly have the authority of an international standards body, this seems like a not-impossible decision. Famous last words, I know. What about 10 decimal time zones?

Ten probably isn’t enough. Keeping in mind that the maximum error caused by the time zone is half of the time that the time zone crosses (and that doesn’t include bizarre political decisions), half a decimal hour is really a pretty major error. Too big. Okay, split it in half. Now you have twenty decimal time zones, each one 1/20 of a day wide. Or, in decimal time, 0:50:0. Or, in “classical” time, about an hour. What, you’re still using classical time?

So, assuming we have no desire to overthrow the GMT hegemony (and really, I have no desire to do so), this means that San Luis Obispo is at about – 3:50. Sounds good to me.

Of course,in order to compute that, I used… DEGREES!? Dividing a circle into 360 parts? That’s CRAZY!