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The surprising whimsy of the Time Zone Database

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Re: The surprising whimsy of the Time Zone Database

#51

Post by Scarblac »

kgwgk wrote: post #41
pezezin wrote: post #40

> I’ve perused the tz repository before, and I always learn something interesting. For example, during WWII Britain adopted double summer time, adding two hours to the clock in the summer and one hour in the winter. My country, Spain, did the same but never fixed it, so we are still in this "double summer time". It is one of the main reasons why Spanish people seemingly do everything later (breakfast, lunch, dinner)…

Other Western European countries like France also switched to German time during the war and kept it afterwards.

Yes, the Netherlands too (we were on +0:20 before).

But Spain is much further to the west.

Re: The surprising whimsy of the Time Zone Database

#52

Post by Majromax »

tempestn wrote: post #28

The comment actually has it backwards. It says BC is moving from daylight to standard time, but should be the opposite. It's got the offset right though.

As far as the timezone file is concerned, it's two changes but one shift. This is covered more fully in the complete news blob rather than the snippet shown at the top. Today, British Columbia moved from Pacific Standard Time (UTC-8) to Pacific Daylight Time (UTC-7); tomorrow the timezone is renamed to Pacific Time.

Unfortunately, the "PT" abbreviation is too short for the timezone database, so while they decide on another form they will temporarily use a bare -7 offset.

Re: The surprising whimsy of the Time Zone Database

#53

Post by russellbeattie »

ithkuil wrote: post #43
russellbeattie wrote: post #27

Just last night some friends brought up the time change tonight and the news from British Columbia, and what the California government has or hasn't done about it currently and in the past and why we haven't just gotten rid of the system already to save us the trouble of adjusting clocks twice a year. And of course, there was instantly a heated debate about whether to permanently choose Standard Time or Daylight Savi…

What is "team DST"? Those who want permanent DST or those who want to do things as they are where DST is on for half of the year?

The first one, though it's just a joke. I think honestly I'm more #TeamJustPickOneAlready.

Re: The surprising whimsy of the Time Zone Database

#54

Post by russellbeattie »

pinkmuffinere wrote: post #30
russellbeattie wrote: post #27

Just last night some friends brought up the time change tonight and the news from British Columbia, and what the California government has or hasn't done about it currently and in the past and why we haven't just gotten rid of the system already to save us the trouble of adjusting clocks twice a year. And of course, there was instantly a heated debate about whether to permanently choose Standard Time or Daylight Savi…

> #teamdaylightsaving Don't talk to me or my son ever again.

LOL. I always enjoy a nice meme callback.

Re: The surprising whimsy of the Time Zone Database

#55

Post by jventura »

Mountain_Skies wrote: post #36
fzeindl wrote: post #20

I once digged into this database out of curiosity and found incredibly detailed research on many edge cases. Like time zones in Germany being temporarily aligned to Moscow during soviet occupancy after World War Two. One particular commenter stood out to me, so I looked him up because I was interested which kind of people spend so much time correcting timezone information. Turns out he was an astrologer and wanted hi…

On the other hand, it was also astrologers that made copyright claims on the database and caused it to become unavailable to the world for a short period of time.

It were not astrologers, it was a company that creates astrology software.. Don't mix people with companies, they are different things! One is there definitely for the money, the other may or may not..

Re: The surprising whimsy of the Time Zone Database

#56

Post by Cyphase »

rawling wrote: post #33
netsharc wrote: post #22

Amusing story of the chaos of timezones in Saudi Arabia and a man who made his own: https://archive.aramcoworld.com/issue/196902/dinner.at.when.... Linked from https://github.com/eggert/tz/blob/main/asia#L3818

I enjoyed getting an instant rate limit screen trying to load that blob (and then the one linked from TFA). I don't think I have anything on my network hammering GH...

I also get that screen on GitHub occasionally, so it's not just you.

Re: The surprising whimsy of the Time Zone Database

#57

Post by [deleted] »

fzeindl wrote: post #20

I once digged into this database out of curiosity and found incredibly detailed research on many edge cases. Like time zones in Germany being temporarily aligned to Moscow during soviet occupancy after World War Two. One particular commenter stood out to me, so I looked him up because I was interested which kind of people spend so much time correcting timezone information. Turns out he was an astrologer and wanted hi…

[deleted]

Re: The surprising whimsy of the Time Zone Database

#58

Post by NewJazz »

robotmlg wrote: post #17
NewJazz wrote: post #14

Is this article finished? There are mentions of excerpts from the database, but the excerpts are not reproduced or linked to, as far as I can tell.

There is a link to the North America file, where all those referenced stories can be found.

Got it, didn't realize they were all in the same file I guess.

Re: The surprising whimsy of the Time Zone Database

#59

Post by grodriguez100 »

pezezin wrote: post #40

> I’ve perused the tz repository before, and I always learn something interesting. For example, during WWII Britain adopted double summer time, adding two hours to the clock in the summer and one hour in the winter. My country, Spain, did the same but never fixed it, so we are still in this "double summer time". It is one of the main reasons why Spanish people seemingly do everything later (breakfast, lunch, dinner)…

Spain is not “double summer time”, it is just on an offset that is off by one hour related to its geographical position.

Re: The surprising whimsy of the Time Zone Database

#60

Post by shagie »

dqv wrote: post #29
themafia wrote: post #16

Earlier quoted context omitted.

You need it to encode or decode past dates to unix time or other time standards. You do not need it to "interpret" past dates. Even then the tzdb only covers _offsets_ within a day. So even without it you can get an answer that is very close to the "correct" answer. For dates at that great of a remove the lack of accuracy to a precise second is rarely a problem. I don't exactly need to schedule a remote video phone c…

> You need it to encode or decode past dates to unix time or other time standards. Which you need to do if > You do not need it to "interpret" past dates. you want to interpret past dates. Mainly you need a historical record of the offsets. Or you're trading inaccuracy of duration measurement from one or two days out of the year to every day of the year by not keeping track of historical offsets or taking them into c…

> It can even work for future dates and times too!

Morocco has some complex logic around Ramadan... which is a moveable festival.

https://github.com/eggert/tz/blob/main/africa#L854

    Rule Morocco 2026 only - Feb 15  3:00 -1:00 -
    Rule Morocco 2026 only - Mar 22  2:00 0 -
    Rule Morocco 2027 only - Feb  7  3:00 -1:00 -
    Rule Morocco 2027 only - Mar 14  2:00 0 -
    Rule Morocco 2028 only - Jan 23  3:00 -1:00 -
    Rule Morocco 2028 only - Mar  5  2:00 0 -
    Rule Morocco 2029 only - Jan 14  3:00 -1:00 -
    Rule Morocco 2029 only - Feb 18  2:00 0 -
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