February 2007 - tz - lists.iana.org

FW: tzdata2006n Brazil incorrect fall-back date 2009-mar-01
by Olson, Arthur David (NIH/NCI) [E] Feb. 8, 2007

Feb. 8, 2007

I'm forwarding this message from Markus Scherer, who is not on the time zone mailing list. Those of you who are on the time zone mailing list should direct replies appropriately. --ado -----Original Message----- From: Markus Scherer [mailto:markus.icu@gmail.com] Sent: Thursday, February 08, 2007 3:10 PM To: tz(a)lecserver.nci.nih.gov Cc: Dave O'Callaghan Subject: Re: tzdata2006n Brazil incorrect fall-back date 2009-mar-01 Dear Dave et al., I reported and subsequently fixed the bug. If you are curious, you can click on the SVN Diffs link near the top of the bug report to see what changed. For questions about using ICU, bugs, support etc. please use the icu-support mailing list: http://icu.sourceforge.net/contacts.html Best regards, markus On 1/22/07, Paul Eggert <eggert(a)cs.ucla.edu> wrote: > "Dave O'Callaghan" <daveoc(a)uk.ibm.com> writes: > > > I have been alerted to this website > > http://icu-project.org/trac/ticket/5470 which describes an issue > > with the Brazil update in tzdata2006n. > > > > Is this true? > > It appears to me to be a problem in the ICU4C's code simpletz.cpp, not > in the tz code or data itself, so you should ask whoever wrote > simpletz.cpp to fix it.

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Re: tzdata2006n Brazil incorrect fall-back date 2009-mar-01
by Paul Eggert Feb. 8, 2007

Feb. 8, 2007

"Dave O'Callaghan" <daveoc(a)uk.ibm.com> writes: > I have been alerted to this website > http://icu-project.org/trac/ticket/5470 which describes an issue with the > Brazil update in tzdata2006n. > > Is this true? It appears to me to be a problem in the ICU4C's code simpletz.cpp, not in the tz code or data itself, so you should ask whoever wrote simpletz.cpp to fix it. The tz data currently says that the fall-back transition in Brazil in 2009 is the last Sunday in February, which will be 2009-02-22, but the ICU4C (?) code apparently does not handle this case correctly. To some extent this is all academic. Judging by past experience, Brazil most likely will change the rules before 2009 rolls around, so the tz data is just guessing about the 2009 transition.

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DST in the news
by Olson, Arthur David (NIH/NCI) [E] Feb. 5, 2007

Feb. 5, 2007

The 2007-02-01 Washington (DC) Post has a front page story, "Clock's Early Spring Forward May Bring About a Few Falls," covering the impending change in US DST rules and the potential consequences. The story is available from http://www.washingtonpost.com; you'll get to register to view the story. --ado

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Mexico revision
by Jesper Norgaard Welen Feb. 4, 2007

Feb. 4, 2007

I have been revising the pages of the Mexican Congress Library at http://www.cddhcu.gob.mx/bibliot/publica/inveyana/polisoc/horver/capitulo5.h tm about timezone changes since 1921 which is also mentioned in the 'northamerica' file (although without the HTM file mentioned). The aim is to bring tz database up-to-date with this information, which is already used as preferred source to Shanks in the 'northamerica' file. I guess then I don't have to argue why I think these pages should have more priority, but rather I would like to point out their deficiencies too before looking at the actual changes to the tz database that I'm recommending. First of all about completeness, I have serious doubt to that these pages are *all* the official Mexican documents that exist about timezone matters - especially concerning the gap of no decrees between 1948 and 1981. In fact, I believe that these decrees are accurate and were followed, but that likely other decrees have not been included in the list, whether there were 33 year gaps or they were smaller. About dates, it seems that most decrees only have a *publication* date, not an effective date. Here is a summary (I named the decrees A to R to have some reference): Decree, Official Publish Date, Effective Date A: 1921-12-20, 1922-01-01 0:00:00 B: 1923-12-00 C: 1927-06-09 D: 1930-11-15 E: 1931-04-28 F: 1932-01-21, 1932-04-01 G: 1942-04-24 H: 1945-11-12 I: 1948-04-05 J: 1981-12-23 K: 1982-11-02 L: 1988-02-17 M: 1989-03-23 N: 1989-03-30 O: 1996-01-04 P: 1997-08-13 Q: 1998-07-31 R: 1999-03-29 the 'northamerica' file states # Here are the discrepancies between Shanks & Pottenger (S&P) and the MLoC. # (In all cases we go with the MLoC.) # S&P report that Baja was at -8:00 in 1922/1923. # S&P say the 1930 transition in Baja was 1930-11-16. # S&P report no DST during summer 1931. # S&P report a transition at 1932-03-30 23:00, not 1932-04-01. Baja at -8:00 seems unlikely, since decree A only mentions -6:00 and -7:00. That the 1930 transition in Baja was 1930-11-16 sounds perfectly plausible to me, I think we should go with Shanks here, and actually it is quite possible that all changes in Mexico (also America/Mexico_City, America/Chihuahua, America/Hermosillo, America/Mazatlan, and America/Tijuana) should be 1930-11-16. No DST during summer 1931 sounds unlikely, see decree E. However some doubt does arise since the decree talks about 'every year' and beginning 1.st. of April each year, while being published nearly a month later (on 1931-04-28). A transition at 1932-03-30 23:00, 1 day and 1 hour before the decree F stated it should be (in fact one of the only Effective Dates of all these decrees) seems extremely unlikely. I don't have a copy of Shanks and Pottenger, so I can't make corrections accordingly. But I think we should believe more in Shanks than these pages for Effective dates if the changes to timezones (the content) are otherwise matching. Now to the actual changes. I am attaching a full 'northamerica' file (version 2007a changed) for convenient difference checking. # Quintana Roo Zone America/Cancun -5:47:04 - LMT 1922 Jan 1 0:12:56 -6:00 - CST 1981 Dec 23 + -5:00 - E%sT 1996 Jan 4 0:00 + -6:00 Mexico E%sT 1997 Oct 26 2:00 -5:00 Mexico E%sT 1998 Aug 2 2:00 That Cancun went from GMT-6 to GMT-5 (no DST involved) at 1981-12-23 is confirmed in decree J. I'm guessing a little bit above, but we have decree O saying explicitly that there are three zones, and one is "all of the national territory except the two other zones". So definitely Cancun most have been on Mexico City time since this decree took effect (sometime on/after 1996-01-04). Decree P then introduces Cancun on GMT-4 during DST and GMT-5 outside, in the end of the DST period defined in decree O. So I assume a smooth transition where Cancun ended their DST from GMT-6 to GMT-5 by simply not switching back the clock to GMT-6, but continuing with GMT-5 until 1998-04-05 where GMT-4 is introduced (DST). # Campeche, Yucatan Zone America/Merida -5:58:28 - LMT 1922 Jan 1 0:01:32 -6:00 - CST 1981 Dec 23 - -5:00 - EST 1982 Dec 2 + -5:00 - EST 1982 Nov 2 -6:00 Mexico C%sT Decree K has publication date 1982-11-02. Would the above effective date 1982-12-02 just by a typo of some kind? I don't know what Shanks date is, but I assume we have nothing better than to go with the publication date. Correct me if I'm wrong, that is quite possible here. # Coahuila, Durango, Nuevo Leon, Tamaulipas Zone America/Monterrey -6:41:16 - LMT 1921 Dec 31 23:18:44 + -7:00 - MST 1927 Jun 10 23:00 + -6:00 - CST 1930 Nov 15 + -7:00 - MST 1931 May 1 23:00 + -6:00 - CST 1931 Oct + -7:00 - MST 1932 Apr 1 - -6:00 - CST 1981 Dec 23 -6:00 Mexico CST 1988 -6:00 US C%sT 1989 + -6:00 Mexico C%sT 2001 Sep 30 02:00 + -6:00 - CST 2002 Feb 20 -6:00 Mexico C%sT This set of changes, although looking complicated, are really quite simple. We have a specific difference for the above four states in decree L of 1988-02-17 applying US style DST in 1988. But there is no evidence that they were any different than Mexico City before or after that year. In fact having GMT-6 unaltered since 1922 to 1988 seems to me extremely unlikely, for instance decree B says that the states from Baja California Sur and Sonora until Veracruz and Oaxaca (exclusively) are all on GMT-7, while Veracruz, Tamaulipas and Oaxaca (and presumably states to the south and east of those) are on GMT-6. Tamaulipas then consists of an exception here, but since this happened before the cutoff date of 1970, we don't need a new timezone for Tamaulipas. Note that I copy the two lines for years 2001-2002 from the America/Mexico_City timezone, although I don't understand them - what is the difference to just using the last line e.g. GMT-6 with Mexico rule, since 1989? # Baja California Zone America/Tijuana -7:48:04 - LMT 1922 Jan 1 0:11:56 -7:00 - MST 1924 -8:00 - PST 1927 Jun 10 23:00 - -7:00 - MST 1930 Nov 15 + -7:00 - MST 1930 Nov 16 - -8:00 - PST 1931 Apr 1 + -8:00 - PST 1931 May 1 23:00 - -8:00 1:00 PDT 1931 Sep 30 + -8:00 1:00 PDT 1931 Oct -8:00 - PST 1942 Apr 24 First I change effective date from 1930-11-15 to 1930-11-16 as per Shanks in the note above. Then I revert the effective date 1931-04-01 to 1931-05-01 23:00 as in the other timezones, because I think it is unlikely that the change happened before the decree E about the change was published (1931-04-28). Also I think this was set as Apr 1 because that is the date that was specified in the decree E, but for all years, not just 1931. September 30 is quite likely also a misinterpretation of the original decree E. It states that every year DST runs from 1.April till 30.th. of September, but that winter time runs from 1.October to 31.st of March. Clearly what is meant is 1930-09-30 24:00 and not 1930-09-30 0:00, or rather 1930-10-01 0:00. Note there is a typo in a note from Debra Goldsmith where 2:OO should be 2:00, above the Indiana definition. I'm not so happy with the Reuter transcript, quite possibly produced in a hurry in Reuters just around the date of the actual event: # From Reuters (2001-09-04): # Mexico's Supreme Court on Tuesday declared that daylight savings was # unconstitutional in Mexico City, creating the possibility the # capital will be in a different time zone from the rest of the nation # next year.... The Supreme Court's ruling takes effect at 2:00 # a.m. (0800 GMT) on Sept. 30, when Mexico is scheduled to revert to # standard time. "This is so residents of the Federal District are not # subject to unexpected time changes," a statement from the court said. The note about the Supreme Court reinstating the DST rules already established by the president, is amusing but perhaps not too relevant. But that the Supreme Court declared daylight saving (not daylight saving*s*) unconstitutional, is plain wrong. Here is a better source (my translation): http://www.conae.gob.mx/wb/CONAE/CONA_2562_breve_historia_del_h ======= Start of translation ======= The first of February 2001 was published in the official newspaper of the federation the presidential decree to establish DST from the First Sunday of May till the Last Sunday of September (five months) in all of the national territory ... Supported by a telephone inquiry of the 24.th. and 25.th. of February 2001, where 239,437 inhabitants of Mexico City where asked their opinion, the mayor of the capital emitted a decree the 26.th. of February, defining that the capital would not implement DST. Additionally, the 5.th. of March 2001 the mayor put forward a constitutional dispute about the validity of the presidential decree published the 1.st. of February 2001. It was the 4.th. of September 2001 that the Supreme Court decided that it was the responsibility of the Congress to determine laws about GMT offset and DST. Congress then approved the current law of DST published in the Official Newspaper 29.th. of December 2001. Finally the 1.st. of March 2002 was published the law about DST during 7 months which is applied each year in Mexico. ======= End of translation ======= In short, the presidential decree was deemed unconstitutional, not daylight saving. Something not mentioned above was that the mayor's decree about setting the time for the capital, was also deemed unconstitutional, in effect a "draw" between the two combattants - it was all about power, of course. The presidential decrees had been a tradition since 1917. But an unconstitutional one, it seems. Regards, - Jesper Nørgaard Welen

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UK news: another attempt to change the clocks likely to fail
by Peter Ilieve Feb. 3, 2007

Feb. 3, 2007

Another attempt to get a bill passed in the UK parliament to move the clocks forward an hour all year got quite a bit of publicity last week. Tim Yeo, a fairly senior figure who has been an environment minister in the past, drew second place in the ballot for private members bills. No doubt mindful of the topicality of climate change, he called his attempt to move the clocks forward an hour the Energy Saving (Daylight) Bill rather than promising extra daylight. The Bill came up for second reading (the first real debate) last Friday, 26 January. It passed a vote (doing much better than Nigel Beard's 2004 attempt) but there weren't enough MPs present for the vote to count for anything. That resulted in the debate being adjourned until tomorrow (2 Feb), but the procedure is such that it is now extremely unlikely to make further progress. The Bill is similar to Nigel Beard's one. It would advance the clocks in England by an hour all year and allow Scotland, Wales and Northern Ireland to decide whether to follow suit or not. The main difference is that it would do this for a trial period, 2008 to 2011, and a review panel would be established to report on this trial. The best place to start for details of this is <http://bills.parliament.uk/DH.asp?title=d> That page has links to the Bill, the debates and a research paper about it. There was also a question asked about this in the Lords on 24 Jan, which can be found in the Lords Hansard at <http://www.publications.parliament.uk/pa/ld200607/ldhansrd/text/ 70124-0001.htm#07012469000005> I asked the person responsible for this at the Department of Trade and Industry for the government's view this morning. He said the government oppose this Bill. I said I wished people would stop trying to change the clocks. `You and me both' he said. :-) I'll send an update if the Bill does make progress. Peter Ilieve peter(a)aldie.co.uk

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time zone question
by A. Diamond Feb. 2, 2007

Feb. 2, 2007

Hello, I just downloaded tzdata and tzcode to update some Linux servers. Thank you for maintaining all this info and code. Just out of curiosity, why does NIH maintain this information instead of NIST? Is it just because someone who happened to be at NIH had the initiative to do it when no one else did? Thanks for your work. Andrew Diamond diamond(a)sheprador.com

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FW: Bulletin C number 33
by Olson, Arthur David (NIH/NCI) [E] Feb. 1, 2007

Feb. 1, 2007

-----Original Message----- From: services.iers(a)obspm.fr [mailto:services.iers@obspm.fr] Sent: Thursday, February 01, 2007 9:49 AM To: adresc1(a)hpopa.obspm.fr Subject: Bulletin C number 33 INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE SERVICE DE LA ROTATION TERRESTRE OBSERVATOIRE DE PARIS 61, Av. de l'Observatoire 75014 PARIS (France) Tel. : 33 (0) 1 40 51 22 26 FAX : 33 (0) 1 40 51 22 91 Internet : services.iers(a)obspm.fr Paris, 1 February 2007 Bulletin C 33 To authorities responsible for the measurement and distribution of time INFORMATION ON UTC - TAI NO positive leap second will be introduced at the end of June 2007. The difference between Coordinated Universal Time UTC and the International Atomic Time TAI is : from 2006 January 1, 0h UTC, until further notice : UTC-TAI = -33 s Leap seconds can be introduced in UTC at the end of the months of December or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every six months, either to announce a time step in UTC, or to confirm that there will be no time step at the next possible date. Daniel GAMBIS Director Earth Orientation Center of IERS Observatoire de Paris, France

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daylight-saving news from UCEI, WA, NZ, WY, TERiX
by Paul Eggert Feb. 1, 2007

Feb. 1, 2007

Some recent news about daylight saving time: Ryan Kellogg and Hendrik Wolff of the University of California Energy Institute have published a paper "Does Extending Daylight Saving Time Save Energy? Evidence from an Australian Experiment", CSEM WP 163 (January 2007) <http://www.ucei.berkeley.edu/PDF/csemwp163.pdf>. Their brief answer is "no". They report that the Australian experiment with DST during the 2000 Olympics did not decrease overall electrical consumption, but it did change usage patterns leading to a higher morning peak load. Western Australian Nationals leader Brendon Gryllis says his party will submit a private member's bill next month, calling for a referendum before October 31 to repeal daylight saving time in Western Australia. Nelson, NZ city councillor Mark Holmes and United Future Party leader Peter Dunne have gathered a petition with 10,000 signatures to extend daylight saving time in New Zealand by three weeks. <http://www.newstalkzb.co.nz/newsdetail1.asp?storyID=110957> The Wyoming Senate's Corporations, Elections and Political Subdivisions Committee voted 3-2 against exempting Wyoming from daylight saving time. In a recent poll 41% of Wyoming's inhabitants want to repeal daylight saving, and 44% want to keep it. <http://www.billingsgazette.net/articles/2007/01/18/news/wyoming/55-time.txt> <http://www.billingsgazette.net/articles/2007/01/17/news/wyoming/38-time.txt> Various companies have announced support for the US daylight-saving time changes in their software, or in older versions of other people's software. My favorite was TERiX, which announced free patches for Solaris 2.5.1 through 2.7, for customers who don't want to bother to run 'zic' themselves.

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