Re: Time zone names (was REMINDER: CharMod Call Today)

Most people really end up using "wall time" when referencing events, and in many
regions that is not a constant offset from GMT (or UTC). When you say that you
have a meeting "Tuesdays at 10:00 PT" (Pacific Time), that carries more (and
different) information than saying "Tuesdays at 10:00 GMT-08:00". For part of
the year -- as a matter of fact, for a *majority* of the year -- it is "Tuesdays
at 10:00 GMT-07:00". The problem is that you have to go look up against the
Olson database or equivalent to determine what the wall time is for any
particular place.

What would truely be useful would be if all those countries of the world that
use summer time could standardize on two dates during the year to switch their
clocks (e.g. 3th Sundays in March and September, near the æquinoctia). Then you
could use three appreviations to fully specify the time without needing to know
detailed daylight conventions:

- Tuesdays at 10:00 GMT-08:00 = constant offset -08:00 from GMT
- Tuesdays at 10:00 GMT-08:00N = GMT-08:00 from Sept-March, GMT-07:00 from
March-Sept
- Tuesdays at 10:00 GMT-08:00S = GMT-08:00 from March-Sept, GMT-07:00 from
Sept-March

(Cross-posting to the ICU list, since there was a recent discussion of timezones
there.)

Mark
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----- Original Message ----- 
From: "Richard Ishida" <[email protected]>
To: "'Jungshik Shin'" <[email protected]>; <[email protected]>
Cc: <[email protected]>
Sent: Mon, 2003 Dec 08 03:13
Subject: Time zone names (was REMINDER: CharMod Call Today)


>
> Hmm.  Some thoughts around the topic...
>
> > [1] Let's not use GMT (obsoleted almost 30 years ago).
>
> Since it's still in vigorous use here, obviously nobody dared tell the
> British about that  ;-)  More seriously I've come across a lot of people
> (not just in Europe) who don't know what UTC is, but recognise GMT - so
> perhaps we should use both.  "UTC/GMT"
>
> > Instead, we have to use UTC. And, 'Eastern' and 'Pacific' are
> > too US-centric, aren't they?
> > :-) US EST and US PST would be better (or UTC -0500 and UTC
>
> Well US EST is pretty US centric too ;-).  I guess the key thing is that
> people from that area recognise the location.
>
> Actually note that EST stands for Eastern Standard Time, which becomes
> EDT Eastern Daylight Time during the summer.  One is UTC-4 and the other
> is UTC-5.  If daylight savings changes at the same time, as it did in
> October, using a city name or "Eastern" may avoid a little confusion
> here.
>
> Btw, these 3 letter abbreviations are potentially problematic in more
> ways than one.  Some areas don't use them at all.  Some acronyms are
> ambiguous, eg. AST where A = Alaska or Atlantic.
>
>
> > -0800). See  (cited in
> > http://bugzilla.mozilla.org/show_bug.cgi?id=224744)
> >
> > Short
> > and sweet:
> >
> http://lists.debian.org/debian-boot/1999/debian-boot-199901/msg00450.htm
> l
>
> >More than you ever wanted to know:
> http://www.apparent-wind.com/gmt-explained.html
>
>
> This and other places actually seem to me to make the point that GMT is
> used as the starting point for time zones around the world.  UTC is for
> GPS and other very precise measurements. Note also
> http://wwp.greenwichmeantime.com/home.htm that says "Greenwich Mean Time
> is international time, the basis of the world time clock.  ... Defines
> date and time and exact time.  The atomic time clock is adjusted by leap
> seconds to maintain synchronicity with GMT."  Not the other way around.
>
>