Some sources say Guatemala will observe DST this year. For instance Steffen Thorsen: http://www.timeanddate.com/worldclock/city.html?n=94 DST starts on Sunday, April 30, 2006 at 12:00 Midnight local standard time DST ends on Sunday, October 1, 2006 at 12:00 Midnight local daylight time TZ database still has no DST since 1991. What is the truth?
I did some searching online. Diario Co Latino, at http://www.diariocolatino.com/internacionales/detalles.asp?NewsID=8079, says in an article dated 2006-04-19 that the Guatemalan government had decided on that date to advance official time by 60 minutes, to lessen the impact of the elevated cost of oil. There is an archived article on mipunto.com (http://www.mipunto.com/punto_noticias/noticia_latin.jsp?tipo=CENTROECO&arch ivo=060419183143.3zxeu5u5.txt) to the same effect. Daylight saving time will last from 2006-04-29 24:00 (Guatemalan standard time) to 2006-09-30 (time unspecified), according to Diario Co Latino; mipunto.com calls it 00:00. Diario Co Latino seems to be the website of a newspaper in San Salvador. Mipunto.com is a Venezuelan site. -- Gwillim Law ----- Original Message ----- From: "Oscar van Vlijmen" <ovv@hetnet.nl> To: "TZ-list" <tz@lecserver.nci.nih.gov> Sent: Saturday, April 22, 2006 10:06 AM Subject: Guatemala DST?
Some sources say Guatemala will observe DST this year. For instance Steffen Thorsen: http://www.timeanddate.com/worldclock/city.html?n=94
DST starts on Sunday, April 30, 2006 at 12:00 Midnight local standard time DST ends on Sunday, October 1, 2006 at 12:00 Midnight local daylight time
TZ database still has no DST since 1991. What is the truth?
Thanks to both of you for the heads-up about Guatemala. And I thought our changes were done with, for this northern-hemisphere spring! I'll issue yet another proposed patch soon, since this change takes effect in a week.
On 22 Apr 2006 at 16:06, Oscar van Vlijmen wrote:
DST [for Guatemala] starts on Sunday, April 30, 2006 at 12:00 Midnight local standard time DST ends on Sunday, October 1, 2006 at 12:00 Midnight local daylight time
I am not commenting on the veracity of the cited material at all, and I quote Oscar only because the quotation serves as an example. I'm not even sure that people on this list are the right ones to complain to, but surely most everyone on this list, must have noticed the ambiguity. I am troubled by the specification of midnight on a certain date. In the old days (and by that I mean roughly before computers were commonly used by non-computer-geeks like us) to keep time, "midnight Tuesday" meant the minute after 11:59 p.m. Tuesday night. I think (but am not sure) that most people still mean that when they say "midnight Tuesday". Midnight _used_to_be_ a synonym for 2400 hrs., the end of the day. But we pretty much don't use 2400 hrs. any more, and "midnight" has become a synonym, in some contexts, for 0000 hrs., the start of the day. So "midnight Tuesday" might refer to the minute before 12:01 a.m. Tuesday morning (Monday night!). Is anyone else concerned? What should be done? Who should do it? -- Dave Cantor Groton, CT 06340-3731 Dave@Cantor.mv.com
"Dave Cantor" <Dave@Cantor.mv.com> writes:
... "midnight Tuesday". Midnight _used_to_be_ a synonym for 2400 hrs., the end of the day.
Yes, that's the usual meaning in English even now, I think.
But we pretty much don't use 2400 hrs. any more, and "midnight" has become a synonym, in some contexts, for 0000 hrs., the start of the day.
Hmm, which contexts are these? Do you have some quotes? I ask because there is a lot of confusion around on this subject. For example, <http://www.physics.nist.gov/News/Releases/questions.html> says that railroads and airlines get around the 12:00 ambiguity by never scheduling departures for either noon or midnight, but I once had a printed airline ticket that said I left LAX at "1200N", meaning noon.
Is anyone else concerned? What should be done? Who should do it?
It's a centuries-old problem, and I'm not sure we can do much about it. For more on this subject please see <http://en.wikipedia.org/wiki/12-hour_clock> (not that it is infallible either...).
On 2006-04-23, Paul Eggert wrote:
"Dave Cantor" <Dave@Cantor.mv.com> writes:
... "midnight Tuesday". Midnight _used_to_be_ a synonym for 2400 hrs., the end of the day.
Yes, that's the usual meaning in English even now, I think.
But we pretty much don't use 2400 hrs. any more, and "midnight" has become a synonym, in some contexts, for 0000 hrs., the start of the day.
Hmm, which contexts are these? Do you have some quotes?
I ask because there is a lot of confusion around on this subject. For example, <http://www.physics.nist.gov/News/Releases/questions.html> says that railroads and airlines get around the 12:00 ambiguity by never scheduling departures for either noon or midnight, but I once had a printed airline ticket that said I left LAX at "1200N", meaning noon.
I recall when I was doing compulsory military service, they always solved this by saying leave ended at 2359 on the day in question. Even for soldiers, this was unambiguous. Greg
On 23 Apr 2006 at 17:48, Greg Black wrote:
I recall when I was doing compulsory military service, they always solved this by saying leave ended at 2359 on the day in question. Even for soldiers, this was unambiguous.
My experience in the military is different from that. When I served in the US Army (from 1967 to 1970), part of the time I served as a company clerk. One of the duties was to close out the sign-in/sign-out log book at midnight every night. The close-out entry looked roughly like this: 2400 Closed out. (rank)(signature) The date was already written somewhere above and wasn't needed in that entry. We were told that times were 0001-2400, and a soldier could sign in (specifically from leave, by the way) at 2400 hrs. One MINUTE later (not one second), the time was 0001, the next day, and a soldier signing in then would be late (assuming, of course, he was due back on the earlier date). Sometimes, there would be personnel waiting for the close-out entry to occur so that they could sign out on leave on the new day. In that case, they would use the time stamp 0000 hrs. Regarding other replies in this string: Yes, I definitely recall seeing airline schedules where 12:00 N meant noon and 12:00 M meant midnight (of the EARLIER day). Sorry, I cannot produce a reference for this, so I guess it has to be considered anecdotal. Using 12:00 M for noon is what I learned in junior high school, back in the 1950's. We were also taught that midnight was properly called 12:00 p.m. (it is the last minute of the ending day, and is therefore 12 hours after noon, which is what 'p.m.' literally means). Also, the rules for changing the clocks for DST were consistent with that: going to DST meant that 1:59 a.m. was followed by 2:00 a.m., and then the next minute was 3:01 a.m. In the other direction, 1:59 a.m. was followed by 2:00 a.m., which then was followed by 1:01 a.m.! Sorry, I have no written references to back up my recollection here, so this, too, is anecdotal. And this is second-hand anecdotal: I recall reading about a case in the mid-1980s where a man was given a parking ticket for parking sometime in the mid-afternoon in a zone marked "No parking 8 a.m. to 12 p.m." The defendant said that 12 p.m. was 12 noon, but the judge said that 12 p.m. was 12 midnight, and the guy had to pay the fine. Again, anecdotal, so sorry. I found a contradictory anecdote here: http://weekendpundit.blogmosis.com/lastweekend/030124.html When I worked as a system manager, I worked around the ambiguity problem by never scheduling anything for exactly 12:00 either a.m. or p.m. I always scheduled things for 00:01, 11:59, 12:01, or 23:59, but I always specified 11:59 a.m. and 12:01 p.m. to make it clear. As for references for usage of the word 'midnight' (as in "Tuesday midnight") to mean the minute before 12:01 a.m. on the particular day, I have no written references, but have heard this in context several times in informal discourse. I did find, another person's statement about the confusion on the web, here: http://archive.tivocommunity.com/tivo-vb/history/topic/58665- 1.html (scroll down to "Posted by Spire"). In the original post which prompted me start this string of discussion, Oscar van Vlijmen quotes:
DST starts on Sunday, April 30, 2006 at 12:00 Midnight local standard time DST ends on Sunday, October 1, 2006 at 12:00 Midnight local daylight time
To me, this is ambiguous. I cannot tell whether those references to midnight mean the midnight which occurs before 12:01 a.m. on Sunday, or the midnight which occurs after 11:59 p.m. on Sunday.
"Dave Cantor" <Dave@Cantor.mv.com> writes:
Using 12:00 M for noon is what I learned in junior high school, back in the 1950's. We were also taught that midnight was properly called 12:00 p.m. (it is the last minute of the ending day, and is therefore 12 hours after noon, which is what 'p.m.' literally means).
Thanks for your recollections. Older editions of the Chicago Manual of Style (CMS) indeed recommended that '12 m.' means noon and '12 p.m.' means midnight. However, this recommendation was removed sometime during the 14th edition of the CMS. Here's my source: Over the years, we issued about ten printings of the fourteenth edition. Each time we reprinted, we corrected errors that had been pointed out since the last printing. In section 8.48 we wanted to eliminate two examples that seemed more confusing than helpful (and 12:00 P.M. is in fact noon). For the fifteenth edition, we have made several clarifications, including the recommendation that numerals not be used for midnight and noon except in the twenty-four-hour system. Note also that the fifteenth recommends writing "a.m." and "p.m.," though the more traditional small capitals are still accepted (but now without periods: AM and PM). <http://www.press.uchicago.edu/Misc/Chicago/cmosfaq/cmosfaq.CMS.html>. So, I don't know the origin of the tradition you were taught in junior high school, but the CMS is now saying that it was an error! I doubt whether that tradition came from the Romans themselves, since the original Latin tradition was that 3 a.m. was three hours before noon (which is what "a.m." literally means), so the Roman 3 a.m. was our 09:00. Hence, in the original Latin tradition, I guess '12 a.m.' and '12 p.m' would both have meant midnight. Wikipedia says that one should use '12 m.n.' instead, where the 'm.n.' means 'media nox', but I'm dubious of this as well. I suspect that the actual Romans almost invariably wrote either 'meridies' for noon, or 'media nox' for midnight, and didn't bother with the 'xii'. For a (modern) example of this, the motto of the RAF No. 409 Nighthawk Squadron during World War II was "Media nox meridies noster" ("Midnight is our noon") <http://www.rcaf.com/squadrons/400series/409squadron.php>. The RAF didn't bother with 'xii', and I'll bet the Romans didn't either, and that "12 m." and "12 p.m." are neologisms, and confusing ones as well.
On Sun, Apr 23, 2006 at 12:14:36AM -0700, Paul Eggert wrote:
I ask because there is a lot of confusion around on this subject. For example, <http://www.physics.nist.gov/News/Releases/questions.html> says that railroads and airlines get around the 12:00 ambiguity by never scheduling departures for either noon or midnight, but I once had a printed airline ticket that said I left LAX at "1200N", meaning noon.
Even worse, I've seen legislative hearings that were scheduled for "12:00 M". The "M" here means... no, not midnight, but meridian --- i.e., noon! I was quite confused about the "midnight meeting" until I was clued in on the "correct" way of reading the notation. --Ken Pizzini
Ken Pizzini <tz.@explicate.org> writes:
On Sun, Apr 23, 2006 at 12:14:36AM -0700, Paul Eggert wrote:
I once had a printed airline ticket that said I left LAX at "1200N", meaning noon.
Even worse, I've seen legislative hearings that were scheduled for "12:00 M". The "M" here means... no, not midnight, but meridian --- i.e., noon!
Yes, that is a dreadful ambiguity. I hope US airlines don't use "1200M" for midnight, though, as that would be ambiguous as to date. A Latin-language nit, though: "M" means "meridies", not "meridian". "Meridies" was an irregularly formed Latin word: it meant "midday" and came from "medius" mid + "dies" day, which were originally combined into "medidies", but the Romans eventually changed the first D to an R. Postea quinta littera sublata, et subrogata r dicta est laurus, ut in auriculis que in inicio audicule dicte sunt, et medidies qui nunc meridies dicitur. ("Later the letter D was removed and replaced by R, so that it was called laurus, as in the words auricule, which was originally audicule, and medidies, now called meridies.") -- Aberdeen Bestiary entry for "laurel" (circa 1200) <http://www.abdn.ac.uk/bestiary/translat/78v.hti> This just goes to show you that the problem with what exactly to call "noon" and "midnight" goes back _millennia_. I agree with Markus Kuhn that "00:00", "12:00", and (let's hope rarely) "24:00" are the best ways to attack the problem nowadays.
"Dave Cantor" wrote on 2006-04-22 22:34 UTC:
On 22 Apr 2006 at 16:06, Oscar van Vlijmen wrote:
DST [for Guatemala] starts on Sunday, April 30, 2006 at 12:00 Midnight local standard time DST ends on Sunday, October 1, 2006 at 12:00 Midnight local daylight time
I am not commenting on the veracity of the cited material at all, and I quote Oscar only because the quotation serves as an example.
I'm not even sure that people on this list are the right ones to complain to, but surely most everyone on this list, must have noticed the ambiguity.
I am troubled by the specification of midnight on a certain date.
In the old days (and by that I mean roughly before computers were commonly used by non-computer-geeks like us) to keep time, "midnight Tuesday" meant the minute after 11:59 p.m. Tuesday night. I think (but am not sure) that most people still mean that when they say "midnight Tuesday". Midnight _used_to_be_ a synonym for 2400 hrs., the end of the day.
But we pretty much don't use 2400 hrs. any more, and "midnight" has become a synonym, in some contexts, for 0000 hrs., the start of the day. So "midnight Tuesday" might refer to the minute before 12:01 a.m. Tuesday morning (Monday night!).
Is anyone else concerned? What should be done? Who should do it?
Government officials who use obsolete and ambiguous terms such as "12:00 midnight" should be gently pointed to the relevant official standards for time notation, which have solved this problem adequately and unambiguously. ISO 8601: 00:00 is midnight at the start of the given date 24:00 is midnight at the end of the given date (= 00:00 of the next day) All this is discussed in great detail, for example, at http://en.wikipedia.org/wiki/12-hour_clock http://en.wikipedia.org/wiki/24-hour_clock http://en.wikipedia.org/wiki/Midnight http://en.wikipedia.org/wiki/ISO_8601 -- Markus Kuhn, Computer Laboratory, University of Cambridge http://www.cl.cam.ac.uk/~mgk25/ || CB3 0FD, Great Britain
On Sat, 22 Apr 2006, Dave Cantor wrote:
Midnight _used_to_be_ a synonym for 2400 hrs., the end of the day.
But we pretty much don't use 2400 hrs. any more, and "midnight" has become a synonym, in some contexts, for 0000 hrs., the start of the day. So "midnight Tuesday" might refer to the minute before 12:01 a.m. Tuesday morning (Monday night!).
shifting the topic slightly, I've noticed that FM Osaka lists their programme times sometimes as times even later than 2400 (which I intuitively but perhaps incorrectly interpret as meaning tomorrow) For example, http://fmosaka.net/mc/ appears to show 'music coaster' as playing at 25:00 -> 27:00 in the japanese text, and 1am - 3am in the english text. (25 = 1+24, 27 = 3+24) The days don't seem to match either -- or rather they do: japanese text seems to say (as much as I can read) mondays->weds at 25:00->27:00, whilst the english says mondays->weds at 1am - 3am. Has anyone seen that before? --
participants (8)
-
Ben Clifford -
Dave Cantor -
Greg Black -
Gwillim Law -
Ken Pizzini -
Markus Kuhn -
Oscar van Vlijmen -
Paul Eggert