[comp.std.internat] International time zones

jriegel@cstemp2.almaden.ibm.com (08/09/89)

Mean Time for a mail program.  I need the 3-letter abbreviation (CET, etc.)
If anyone has such a list, please mail it to me.

-Jeff
jriegel@ibm.com

devine@shodha.dec.com (Bob Devine) (08/10/89)

In article <993@ks.UUCP>, jriegel@cstemp2.almaden.ibm.com writes:
> I need the 3-letter abbreviation (CET, etc.) [for time zones]
> If anyone has such a list, please mail it to me.
> 
> jriegel@ibm.com

  Unfortunately there is no list.  There are some accepted 3 letter
abbreviations that are used in the English speaking countries but
each country tends to call the timezones that pass through them
a different name (why...that's un-American! ;-).

  Even for English speaking countries some of the timezones abbreviations
are not 3 letters long (eg., Alaska-Hawaii timezone is AHST).

  I suggest that you use English names where appropriate and a
combination of UTC and offset for the others.

Bob Devine

rgt@hpfcdc.HP.COM (Ron Tolley) (08/12/89)

>> I need the 3-letter abbreviation (CET, etc.) [for time zones]
>> If anyone has such a list, please mail it to me.
>> 
>> jriegel@ibm.com
> 
>   Unfortunately there is no list.  There are some accepted 3 letter
> abbreviations that are used in the English speaking countries but
> each country tends to call the timezones that pass through them
> a different name (why...that's un-American! ;-).
>
> Bob Devine

A resource which I have not taped but I know exists is the timezone page of
international air line flight schedules.  Several times I have glanced at it
as I passed by.  It contains all of the current offsets from UTC and may also
give abbreviations for each time zone along with the standard name.

Ron Tolley

ljdickey@water.waterloo.edu (Lee Dickey) (08/17/89)

In article <383@shodha.dec.com> devine@shodha.dec.com (Bob Devine) writes:
>In article <993@ks.UUCP>, jriegel@cstemp2.almaden.ibm.com writes:
>> I need the 3-letter abbreviation (CET, etc.) [for time zones]
>> If anyone has such a list, please mail it to me.
 
>  Unfortunately there is no list.  There are some accepted 3 letter
>abbreviations that are used in the English speaking countries but
>each country tends to call the timezones that pass through them
>a different name ...

>  I suggest that you use English names where appropriate and a
>combination of UTC and offset for the others.

I agree with this.  Better yet, just use UTC.

I recall one discussion about two years ago in which it was observed
that two different zones had the same three letter code:
one was "Bering Strait Time", the other "British Summer Time".

-- 
    L. J. Dickey, Faculty of Mathematics, University of Waterloo.
	ljdickey@water.UWaterloo.ca	ljdickey@water.BITNET
	ljdickey@water.UUCP		..!uunet!watmath!water!ljdickey
	ljdickey@water.waterloo.edu	

domo@riddle.UUCP (Dominic Dunlop) (08/18/89)

In article <1043@riddle.UUCP> domo@riddle.UUCP (that's me) wrote:
>>In article <993@ks.UUCP>, jriegel@cstemp2.almaden.ibm.com writes:
>> I need the 3-letter abbreviation (CET, etc.) [for time zones]
>
>Coincidentally, I have just ordered IS 8601:1988 ``Data elements and
>interchange formats -- Information interchange -- representation of dates
>and times''.  If it has anything to say about the names of timezones, I'll
>post the good news to this group.

Well, it arrived, and it punts on the issue.  The standard represents dates
and times entirely as numbers with a little punctuation thrown in as an
option.  Put Z after a time and it is taken to mean UTC (Greenwich Mean
Time to traditionalists); put a sign and a two or four digit offset, and
you have a time displaced from UTC by that number of hours (two digits) or
by hours and minutes (four digits).  Three-letter zone names are not
mentioned at all (which is consistent: the names of months and days of the
week do not get a look in either).
-- 
Dominic Dunlop
The Standard Answer Ltd., using Sphinx' facilities (for which much thanks)
domo@sphinx.co.uk

otto@tukki.jyu.fi (Otto J. Makela) (08/22/89)

I wrote this program quite some time ago...
Since I've seen CET in place of MET, is this standard ?
Who can add to these zone names ?
--
	/*	Display the time zone names with the minute differences given as
		argument.  If "-" is given as argument, switch DST mode */
	/*	Add: automatic setting of DST depending on current date */
#include	<stdio.h>
#include	"config.h"
char *timezone(int zone, int dst);
main(argc,argv)
int argc;
char *argv[];	{
	register int i,j;
	int arg,dst=0;
 
#ifdef	MSDOS
	*argv="timezone";
#endif
	if(argc<2)	{
		fprintf(stderr,"usage: %s [-] minutes_east_of_greenwich...\n",*argv);
		return(1);
	}
 
	for(arg=1; arg<argc; arg++)
		if(*argv[arg]=='-' && !argv[arg][1])
			dst=!dst;
		else	{
			i=atoi(argv[arg]); j=(i<0)?-i:i;
			printf("%s: %4d minutes (%02dh%02dm) %s of greenwich %s"
				"is \"%s\"\n",*argv,j,j/60,j%60,i>0?"east":"west",
				dst?"during DST ":"",timezone(i,dst));
		}
}
 
	/*	The arguments are the number of minutes of time you are eastward from
	 *	Greenwich and whether DST is in effect.  It returns pointer to a string
	 *	giving the name of the local timezone.
	 *
	 *	Sorry, I don't know all the names.
	 */
 
static struct zone {
	int	offset;
	char	*stdzone;
	char	*dlzone;
} zonetab[] = {
	1*60, "MET", "MET DST",	/* Middle European */
	2*60, "EET", "EET DST",	/* Eastern European */
	-4*60, "AST", "ADT",	/* Atlantic */
	-5*60, "EST", "EDT",	/* Eastern */
	-6*60, "CST", "CDT",	/* Central */
	-7*60, "MST", "MDT",	/* Mountain */
	-8*60, "PST", "PDT",	/* Pacific */
#ifdef notdef
	/* there's no way to distinguish this from WET */
	0, "GMT", 0,			/* Greenwich */
#endif
	0*60, "WET", "WET DST",	/* Western European */
 
	/* Do they use DST in Australia ? */
	10*60, "EST", "EST",	/* Aust: Eastern */
	10*60-30, "CST", "CST",	/* Aust: Central */
	8*60, "WST", "WST",		/* Aust: Western */
	-1
};
 
char *timezone(zone, dst)
{
	register struct zone *zp;
	static char czone[10];
	char sign = '+';
	register char *p, *q;
	char *getenv(), *index();
 
	for (zp=zonetab; zp->offset!=-1; zp++)
		if (zp->offset==zone) {
			if (dst && zp->dlzone)
				return(zp->dlzone);
			if (!dst && zp->stdzone)
				return(zp->stdzone);
		}
 
		/* Not a standard zone, give it as { "+" | "-" } 4digit format */
	if (zone<0) {
		zone = -zone;
		sign = '-';
	}
	sprintf(czone, "%c%02d%02d", sign, zone/60, zone%60);
	return(czone);
}

-- 
* * * Otto J. Makela (otto@jyu.fi, MAKELA_OTTO_@FINJYU.BITNET) * * * * * * *
* Phone: +358 41 613 847, BBS: +358 41 211 562 (CCITT, Bell 2400/1200/300) *
* Mail: Kauppakatu 1 B 18, SF-40100 Jyvaskyla, Finland, EUROPE             *
* * * freopen("/dev/null","r",stdflame); * * * * * * * * * * * * * * * * * *

henry@utzoo.uucp (Henry Spencer) (08/22/89)

In article <1177@tukki.jyu.fi> otto@tukki.jyu.fi (Otto J. Makela) writes:
>I wrote this program quite some time ago...
>Since I've seen CET in place of MET, is this standard ?
>Who can add to these zone names ?

There is *NO* standard set of timezone names, and you are asking for trouble
if you assume there is.  For example, there are at least two different
expansions for "BST".  (That one has actually caused trouble.)
-- 
V7 /bin/mail source: 554 lines.|     Henry Spencer at U of Toronto Zoology
1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu

rayan@cs.toronto.edu (Rayan Zachariassen) (08/23/89)

Here is a list of timezone symbols, originally derived from a table of
Rich Wales' I believe.  If you have any additions to this list, please let
me know.

	"A",		StdZone,	60,	/* UTC+1h */
	"ACSST",	DstZone,	630,	/* Cent. Australia */
	"ACST",		StdZone,	570,	/* Cent. Australia */
	"ADT",		DstZone,	-180,	/* Atlantic (Canada) */
	"AESST",	DstZone,	660,	/* E. Australia */
	"AEST",		StdZone,	600,	/* E. Australia */
	"AST",		StdZone,	-240,	/* Atlantic (Canada) */
	"AWSST",	DstZone,	540,	/* W. Australia */
	"AWST",		StdZone,	480,	/* W. Australia */
	"B",		StdZone,	120,	/* UTC+2h */
	"BST",		DstZone,	60,	/* Great Britain */
	"C",		StdZone,	180,	/* UTC+3h */
	"CDT",		DstZone,	-300,
	"CST",		StdZone,	-360,
	"D",		StdZone,	240,	/* UTC+4h */
	"DST",		nilDate,	0,
	"E",		StdZone,	300,	/* UTC+5h */
	"EDT",		DstZone,	-240,
	"EET",		StdZone,	120,	/* Eastern Europe */
	"EETDST",	DstZone,	180,	/* Eastern Europe */
	"EST",		StdZone,	-300,
	"F",		StdZone,	360,	/* UTC+6h */
	"G",		StdZone,	420,	/* UTC+7h */
	"GMT",		StdZone,	0,
	"H",		StdZone,	480,	/* UTC+8h */
	"HDT",		DstZone,	-540,	/* Hawaii/Alaska */
	"HST",		StdZone,	-600,	/* Hawaii/Alaska */
	"I",		StdZone,	540,	/* UTC+9h */
	"IST",		StdZone,	120,	/* Israel */
	"K",		StdZone,	600,	/* UTC+10h */
	"L",		StdZone,	660,	/* UTC+11h */
	"M",		StdZone,	720,	/* UTC+12h */
	"MDT",		DstZone,	-360,
	"MET",		StdZone,	60,	/* Central Europe */
	"METDST",	DstZone,	120,	/* Central Europe */
	"MST",		StdZone,	-420,
	"N",		StdZone,	-60,	/* UTC-1h */
	"NDT",		DstZone,	-150,	/* Nfld. (Canada) */
	"NST",		StdZone,	-210,	/* Nfld. (Canada) */
	"O",		StdZone,	-120,	/* UTC-2h */
	"P",		StdZone,	-180,	/* UTC-3h */
	"PDT",		DstZone,	-420,
	"PST",		StdZone,	-480,
	"Q",		StdZone,	-240,	/* UTC-4h */
	"R",		StdZone,	-300,	/* UTC-5h */
	"S",		StdZone,	-360,	/* UTC-6h */
	"T",		StdZone,	-420,	/* UTC-7h */
	"U",		StdZone,	-480,	/* UTC-8h */
	"UT",		StdZone,	0,
	"UTC",		StdZone,	0,
	"V",		StdZone,	-540,	/* UTC-9h */
	"W",		StdZone,	-600,	/* UTC-10h */
	"WET",		StdZone,	0,	/* Western Europe */
	"WETDST",	DstZone,	60,	/* Western Europe */
	"X",		StdZone,	-660,	/* UTC-11h */
	"Y",		StdZone,	-720,	/* UTC-12h */
	"YDT",		DstZone,	-480,	/* Yukon */
	"YST",		StdZone,	-540,	/* Yukon */
	"Z",		StdZone,	0,	/* UTC */

henry@utzoo.uucp (Henry Spencer) (08/23/89)

In article <89Aug22.153031edt.10647@neat.cs.toronto.edu> rayan@cs.toronto.edu (Rayan Zachariassen) writes:
>	"BST",		DstZone,	60,	/* Great Britain */

Also Bering Standard Time, on the other side of the world.  Some software
will assume one and some the other.
-- 
V7 /bin/mail source: 554 lines.|     Henry Spencer at U of Toronto Zoology
1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu

devine@shodha.dec.com (Bob Devine) (08/25/89)

  Here is the official list of standard timezones.  There are
two ways of naming the timezone -- zone numbers and zone letters.
Negative zone numbers are east of 0 degrees latitude (the Prime
Meridian); positive numbers are west (note: this is opposite the
Unix convention).

   Degrees     EAST    EAST        WEST    WEST
   East/West   zone    zone        zone    zone   (N. American
   of 0 long.  number  letter      number  letter  zone names)
       0         0       Z           0       Z
      15        -1       A           1       N
      30        -2       B           2       O
      45        -3       C           3       P
      60        -4       D           4       Q (Atlantic ST)
      75        -5       E           5       R (Eastern ST)
      90        -6       F           6       S (Central ST)
     105        -7       G           7       T (Mountain ST)
     120        -8       H           8       U (Pacific ST)
     135        -9       I           9       V (Yukon ST)
     150       -10       K          10       W (Alaska-Hawaii ST)
     165       -11       L          11       X (Bering ST)
     180       -12       M          12       Y

  Note that there is no `j' zone.  In addition to the above 24 zones,
there are some country-specific `timezones'.  The Newfoundland
province is at +3 1/2; Venezuela is at +5 1/2; India uses -5 1/2;
and Iran uses -3 1/2.  For the really different consider that
Saudi Arabia follows its own rule for setting clocks by using the
time at sundown as midnight; Afghanistan may still (unless the
Soviet invasion forced a change) use a time that is -4 hourse 26 minutes
from UTC.  There are probably other exceptions too.

  All names given to the timezones are very country- and language-
specific.  On the coincidental matching of zone names (such as for
the USA and Canada), the zones are still different due to the
handling of daylight saving time rules.

Bob Devine

mark@bdblues.inria.fr (Mark James) (08/28/89)

The time zone lists that people have been posting seem to ignore the
fact that there are at least 26 hours going at any one time.  Consider:

     New Zealand Daylight Savings Time     Z+13
     Tonga Standard Time                   Z+13

(Or, in devine@shodha.dec.com (Bob Devine)'s `official' terms, -13.)

The latter case is especially interesting.  The Kingdom of Tonga
covers three island chains that sprawl on either side of the 180th
meridian; although the bulk of the territory, and nearly all of the
population, is east of 180, the Date Line was bent to the east so that
Tonga would have the same day as its chief trading partners in the
then mainly British South Pacific.  Tonga is officially Methodist,
because the king is, but there is a sizeable Mormon minority.  Now
Mormons celebrate their Sabbath on Saturday, which was unacceptable to
the very devout king; so the Mormon church in Tonga simply declared
the bend in the Date Line null and void, so that their Saturday
corresponded with everyone else's Sunday.  Ah, the tropics...

Luckily, Tonga, being tropical, has no use for daylight savings time,
so there is (to my knowledge) no Z+14.

### T. Mark James           #### opinions, errors etc are my own ###
### mark@bdblues.altair.fr  #### "Sure, living in the future is like
### +33 (1) 39 63 53 93     ####  having bees live in your head.
################################  But, there they are..."

wales@valeria.cs.ucla.edu (Rich Wales) (08/31/89)

In article <392@shodha.dec.com>
devine@shodha.dec.com (Bob Devine) writes:

	Here is the official list of standard timezones.  There are two
	ways of naming the timezone -- zone numbers and zone letters.
	Negative zone numbers are east of 0 degrees latitude (the Prime
	Meridian); positive numbers are west (note: this is opposite the
	Unix convention).

The sign convention, in fact, goes the other way.  Negative numbers are
used west of Greenwich (i.e., earlier than UTC -- *subtract* the amount
from UTC to get the local time), while positive numbers are used east of
Greenwich (i.e., later than UTC -- *add* the amount to UTC to get the
local time).

If you used ARPA RFC822 as your source, you should be aware that RFC822
got the signs wrong in its definition of the one-letter zone names.  For
example, zone "U" (Pacific Standard Time) is -8, not +8 -- RFC822 to the
contrary notwithstanding.  This error is well known among the initiated
:-} and has been noted in some subsequent RFC discussing Internet host
requirements, but RFC822 itself was not corrected.

	In addition to the above 24 zones, there are some country-
	specific `timezones'.  The Newfoundland province is at +3 1/2;

Actually -3:30, not +3:30; see above.

In Canada, BTW, TV programs are generally broadcast at the same time in
each time zone *except* Newfoundland; residents of "The Rock" watch TV
shows at the same time as people in the Atlantic provinces (New Bruns-
wick, Nova Scotia, and Prince Edward Island), at a local time half an
hour later than in other provinces.  This custom has given rise in Can-
ada to such jokes as "the world will end tonight at midnight (12:30 New-
foundland)".

	Venezuela is at +5 1/2;

According to the 1984 World Radio/TV Handbook, Venezuela uses UTC-4.
You may have been thinking of Surinam (formerly Dutch Guiana), which
uses UTC-3:30 as its time zone.

No part of South America is far enough to the west to justify using
UTC-5:50 as its time zone.  The only country that might reasonably con-
sider this time zone is Costa Rica -- and they use UTC-6.

	India uses -5 1/2; and Iran uses -3 1/2.

Again, as indicated above, reverse the signs:  +5:30 and +3:30.

	For the really different, consider that Saudi Arabia follows its
	own rule for setting clocks by using the time at sundown as mid-
	night;

Saudi Arabia used to do this, but stopped the practice some time ago and
now uses the UTC+3 zone.

	Afghanistan may still (unless the Soviet invasion forced a
	change) use a time that is -4 hours 26 minutes from UTC.

Afghanistan has used UTC+4:30 for some time.  This change may indeed
have arisen from the Soviet invasion; I don't have enough information at
hand to verify whether this is so or not.

	On the coincidental matching of zone names (such as for the USA
	and Canada), the zones are still different due to the handling
	of daylight saving time rules.

Canada has, for convenience' sake, followed along with whatever the USA
has done with respect to daylight savings time for some time now.

Back to Newfoundland for a minute.  Newfoundland briefly experimented
with "double daylight savings time" -- moving clocks *two* hours ahead
in the summer.  I don't think they are doing this any more, though.

-- Rich Wales // UCLA Computer Science Department // +1 (213) 825-5683
   3531 Boelter Hall // Los Angeles, California 90024-1596 // USA
   wales@CS.UCLA.EDU      ...!(uunet,ucbvax,rutgers)!cs.ucla.edu!wales
"Work _for_?!?  I don't work _for_ anybody!  I'm just having fun."

wales@valeria.cs.ucla.edu (Rich Wales) (08/31/89)

In article <1389@inria.inria.fr> mark@bdblues.altair.fr writes:

	The Kingdom of Tonga covers three island chains that sprawl on
	either side of the 180th meridian . . . .  [T]he Date Line was
	bent to the east so that Tonga would have the same day as its
	chief trading partners in the then mainly British South Pacific.
	Tonga is officially Methodist, because the king is, but there is
	a sizeable Mormon minority.  Now Mormons celebrate their Sabbath
	on Saturday . . .

There is indeed a sizable Mormon minority in Tonga.  However, Mormons
do not observe the Sabbath on Saturday; our day of rest and worship is
Sunday.  (Being a Mormon myself, I know. :-})

	. . . so the Mormon church in Tonga simply declared the bend in
	the Date Line null and void, so that their Saturday corresponded
	with everyone else's Sunday.

Are you, perhaps, thinking of the Seventh-Day Adventists?  SDA's do, of
course, observe the Sabbath on Saturday (actually, Friday sundown to
Saturday sundown, if I'm not mistaken) -- and I understand they consider
the question of exactly *which* day to worship on to be important enough
that I could easily believe that Adventists in Tonga might reject the
way the International Date Line was drawn.

Perhaps some SDA on the net could clarify this point.  If this was in
fact an issue for them in Tonga, I assume most Adventists would be aware
of it and could confirm it.

-- Rich Wales // UCLA Computer Science Department // +1 (213) 825-5683
   3531 Boelter Hall // Los Angeles, California 90024-1596 // USA
   wales@CS.UCLA.EDU      ...!(uunet,ucbvax,rutgers)!cs.ucla.edu!wales
"Work _for_?!?  I don't work _for_ anybody!  I'm just having fun."

mark@bdblues.inria.fr (Mark James) (08/31/89)

In article <26808@shemp.CS.UCLA.EDU> wales@CS.UCLA.EDU (Rich Wales) writes:
>
>There is indeed a sizable Mormon minority in Tonga.  However, Mormons
>do not observe the Sabbath on Saturday; our day of rest and worship is
>Sunday.  [...]
>Are you, perhaps, thinking of the Seventh-Day Adventists?

Of course I was; my apologies to Mormons.

BTW, now that Afghanistan and Saudi Arabia seem to have aligned their
time zones on Greenwich half-hour boundaries, this leaves, as my
nominee for the weirdest time zone, Nepal; they use Z+05:40 (or at
least they did as recently as 1984).

And on the subject of Z+13 zones:  Could this be the missing `J' zone?
(-;

### T. Mark James           #### opinions, errors etc are my own ###
### mark@bdblues.altair.fr  #### "Sure, living in the future is like
### +33 (1) 39 63 53 93     ####  having bees live in your head.
################################  But, there they are..."

devine@shodha.dec.com (Bob Devine) (09/01/89)

In article <26807@shemp.CS.UCLA.EDU>, wales@valeria.cs.ucla.edu (Rich Wales) writes:
> 	Negative zone numbers are east of 0 degrees latitude (the Prime
> 	Meridian); positive numbers are west (note: this is opposite the
> 	Unix convention).
> 
> The sign convention, in fact, goes the other way.
> If you used ARPA RFC822 as your source, you should be aware that RFC822
> got the signs wrong in its definition of the one-letter zone names.

  You are right.  I had first entered it correctly, checked some of
the reference material and then reversed it!  Naturally one of the
references was RFC822.  The other was Doris Doane's "Time Changes in
The USA".  My parenthetical comment about "unix is opposite" is correct
and should have pointed out to me my error.  Checking a reference by
NIST (was NBS) shows the east=positive and west=negative rule.  Arrgh!

Bob Devine (never believe two random references....)

henry@garp.mit.edu (Henry Mensch) (09/09/89)

*sigh*

all we need now is an xclock which understands all this (or, at least
one which will take an offset ... for X11R3, that is).

# Henry Mensch    /   <henry@garp.mit.edu>   /   E40-379 MIT,  Cambridge, MA
# <hmensch@uk.ac.nsfnet-relay> / <henry@tts.lth.se> / <mensch@munnari.oz.au>