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Time zones in xkcd #1883
by Tim Parenti Aug. 30, 2017

Aug. 30, 2017

Today's xkcd by Randall Munroe (2017-08-30) shows how time zones can throw a wrench into supervillians' plans: https://www.xkcd.com/1883/ -- Tim Parenti

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Fiji DST change?
by Magnus Bengtsson Aug. 28, 2017

Aug. 28, 2017

IATA has sent out the following message: " Please be advised of the following 2017/18 DST dates for Fiji. Please amend the entry for Fiji in Appendix F of your SSIM MAR17 issue to reflect the following: Country Time Standard - - - DST Start - - - - - - DST End - - - DST Name Zone Variation Time Date Time Date Variation Fiji FJ +1200 1400 04NOV17 1400 13JAN18 +1300 " The end date (13JAN18) does not seem to conform to the current rule in tzdata2017b. I can't find any information about this on http://www.fiji.gov.fj Does anyone have any more information? /Magnus Bengtsson

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[PROPOSED] Adjust official transition for Turks & Caicos
by Paul Eggert Aug. 27, 2017

Aug. 27, 2017

* NEWS: Adjust. * northamerica (America/Grand_Turk): Switch 2018-03-11 03:00, not 2018-04-01. --- NEWS | 2 +- northamerica | 8 +++++++- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/NEWS b/NEWS index 0909112..55c06f7 100644 --- a/NEWS +++ b/NEWS @@ -19,7 +19,7 @@ Unreleased, experimental changes at 02:00. (Thanks to Steffen Thorsen.) Turks & Caicos will switch from -04 all year to -05 with US DST on - 2018-04-01 at 00:00. This affects UT offsets starting 2018-11-04 + 2018-03-11 at 03:00. This affects UT offsets starting 2018-11-04 at 02:00. (Thanks to Steffen Thorsen.) Changes to past time stamps diff --git a/northamerica b/northamerica index 42529de..93655fa 100644 --- a/northamerica +++ b/northamerica @@ -3390,12 +3390,18 @@ Zone America/Miquelon -3:44:40 - LMT 1911 May 15 # St Pierre # Time, during the winter months with effect from April 2018 ... # https://www.gov.uk/government/news/turks-and-caicos-post-cabinet-meeting-st… # +# From Paul Eggert (2018-08-26): +# The date of effect of the spring 2018 change appears to be March 11, +# which makes more sense. See: Hamilton D. Time change back +# by March 2018 for TCI. Magnetic Media. 2018-08-25. +# http://magneticmediatv.com/2017/08/time-change-back-by-march-2018-for-tci/ +# # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone America/Grand_Turk -4:44:32 - LMT 1890 -5:07:11 - KMT 1912 Feb # Kingston Mean Time -5:00 - EST 1979 -5:00 US E%sT 2015 Nov Sun>=1 2:00 - -4:00 - AST 2018 Apr + -4:00 - AST 2018 Mar 11 3:00 -5:00 US E%sT # British Virgin Is -- 2.7.4

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[PATCH] * tz-art.htm (Jokes): Add Keillor joke on tz security.
by Paul Eggert Aug. 25, 2017

Aug. 25, 2017

--- tz-art.htm | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/tz-art.htm b/tz-art.htm index abe8eb3..a42361f 100644 --- a/tz-art.htm +++ b/tz-art.htm @@ -549,6 +549,14 @@ yesterday daylight [saving] time ended. Right now it's basically midnight." (Conan O'Brien on the 2010-11-08 premiere of Conan.) </li> <li> +"And now, driving to California, I find that I must enter a password +in order to change the time zone on my laptop clock. Evidently, +someone is out to mess up my schedule and my clock must be secured." +(Garrison Keillor, +"<a href="http://www.garrisonkeillor.com/weve-never-been-here-before/">We've +never been here before</a>", 2017-08-22) +</li> +<li> "Well, in my time zone that's all the time I have, but maybe in your time zone I haven't finished yet. So stay tuned!" (Goldie Hawn, Rowan & Martin's Laugh-In No. 65, 1970-03-09) -- 2.7.4

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Fixed typos
by Dominique Pellé Aug. 21, 2017

Aug. 21, 2017

Hi Following patch fixes various typos: diff --git a/asia b/asia index e26ef1b..7518e0c 100644 --- a/asia +++ b/asia @@ -900,7 +900,7 @@ Zone Asia/Dili 8:22:20 - LMT 1912 Jan 1 # From Paul Eggert (2017-04-20): # Good luck trying to nail down old timekeeping records in India. # "... in the nineteenth century ... Madras Observatory took its magnetic -# measurements in Göttingen time, its meterological measurements on Madras +# measurements in Göttingen time, its metrological measurements on Madras # (local) time, dropped its time ball on Greenwich (ocean navigator's) time, # and distributed civil (local time)." -- Bartky IR. Selling the time: # 19th-century timekeeping in america. Stanford U Press (2000), 247 note 19. @@ -917,7 +917,7 @@ Zone Asia/Dili 8:22:20 - LMT 1912 Jan 1 # # "In 1870 ... Madras time - 'now used by the telegraph and regulated from the # only government observatory' - was suggested as a standard railway time, -# first to be dopted on the Great Indian Peninsular Railway (GIPR).... +# first to be adopted on the Great Indian Peninsular Railway (GIPR).... # Calcutta, Bombay, and Karachi, were to be allowed to continue with their # local time for civil purposes." - Prasad R. Tracks of Change: Railways and # Everyday Life in Colonial India. Cambridge University Press (2016), 145. diff --git a/australasia b/australasia index 6bf0f0a..1e38db7 100644 --- a/australasia +++ b/australasia @@ -1306,7 +1306,7 @@ Zone Pacific/Wallis 12:15:20 - LMT 1901 # http://abc.net.au/news/regionals/neweng/monthly/regeng-22jul1999-1.htm # (1999-07-22). For now, we'll wait to see if this really happens. # -# Victoria will following NSW. See: +# Victoria will follow NSW. See: # Vic to extend daylight saving (1999-07-28) # http://abc.net.au/local/news/olympics/1999/07/item19990728112314_1.htm # diff --git a/backzone b/backzone index 69f6a95..255c4a6 100644 --- a/backzone +++ b/backzone @@ -559,7 +559,7 @@ Zone Europe/Guernsey -0:10:09 - LMT 1913 Jun 18 # Time Act in 1883 and including additional confirmation of some of # the dates of the 'Summer Time' orders originating at # Westminster. There is a little uncertainty as to the starting date -# of the first summer time in 1916 which may have be announced a +# of the first summer time in 1916 which may have been announced a # couple of days late. There is still a substantial number of # documents to work through, but it is thought that every GB change # was also implemented on the island. diff --git a/europe b/europe index 0620db6..8cc55e8 100644 --- a/europe +++ b/europe @@ -2303,7 +2303,7 @@ Zone Europe/Bucharest 1:44:24 - LMT 1891 Oct # http://itar-tass.com/obschestvo/1333711 # http://www.pravo.gov.ru:8080/page.aspx?111660 # http://www.kremlin.ru/acts/46279 -# From October 26, 2014 the new Russian time zone map will looks like this: +# From October 26, 2014 the new Russian time zone map will look like this: # http://www.worldtimezone.com/dst_news/dst_news_russia-map-2014-07.html # From Paul Eggert (2006-03-22): diff --git a/southamerica b/southamerica index 6038c3b..a07da71 100644 --- a/southamerica +++ b/southamerica @@ -1076,7 +1076,7 @@ Zone America/Rio_Branco -4:31:12 - LMT 1914 # the following source, cited by Oscar van Vlijmen (2006-10-08): # [1] Chile Law # http://www.webexhibits.org/daylightsaving/chile.html -# This contains a copy of a this official table: +# This contains a copy of this official table: # Cambios en la hora oficial de Chile desde 1900 (retrieved 2008-03-30) # http://web.archive.org/web/20080330200901/http://www.horaoficial.cl/cambio.… # [1] needs several corrections, though.

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Fiji DST change
by Dominic Fok Aug. 21, 2017

Aug. 21, 2017

Hi all, Here is a daylight saving order for Fiji DST in 2018 to finish on the 14th, rather than the 21st (local time). I believe IATA have also sent out a similar memo. Could tzdatabase be updated please? Thanks, D Good planets are hard to find - please think of the environment before you print this email. ____________________________________________________________________ CAUTION - This message may contain privileged and confidential information intended only for the use of the addressee named above. If you are not the intended recipient of this message you are hereby notified that any use, dissemination, distribution or reproduction of this message is prohibited. If you have received this message in error please notify Air New Zealand immediately. Any views expressed in this message are those of the individual sender and may not necessarily reflect the views of Air New Zealand. _____________________________________________________________________ For more information on the Air New Zealand Group, visit us online at http://www.airnewzealand.com _____________________________________________________________________

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Madras Observatory reports [RE: Fixed typos]
by Gent, R.H. van (Rob) Aug. 20, 2017

Aug. 20, 2017

In the 19th century it was quite common for an astronomical observatory to also make meteorological and magnetic observations. https://archive.org/details/meteorological1841to45madruoft https://archive.org/details/magneticalobser00indgoog The 19th-century Madras Observatory reports can be found at http://adsabs.harvard.edu/historical.html Rob van Gent -----Original Message----- From: tz-bounces(a)iana.org [mailto:tz-bounces@iana.org] On Behalf Of J William Piggott Sent: 20 August 2017 14:22 To: Ice Karma (J. Connell) 「氷宿縁」; Time Zone Mailing List Subject: Re: [tz] Fixed typos On 08/20/2017 12:17 AM, Ice Karma (J. Connell) 7¿ wrote: > I suspect "meterological" in the first diff hunk should actually read > "meteorological", rather than "metrological". It seems unlikely that the Madras Observatory was making weather reports. I imagine the author intended to write "astronomical" measurements. However, since it is written as a direct quote the mistake should be left as is, possibly with [sic]? > > â¬Ice Karma >

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Syntax highlighting for Sublime Text
by Gilmore Davidson Aug. 16, 2017

Aug. 16, 2017

Hi, I’ve created some tzdata syntax highlighting rules for the Sublime Text editor: https://packagecontrol.io/packages/zoneinfo <https://packagecontrol.io/packages/zoneinfo> I have no idea if anyone other than me uses that particular text editor for looking at tzdata files. But I thought I’d mention it just in case it’s useful to someone. Cheers, Gil

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[PROPOSED] * NEWS: Add "Briefly:" for changes so far.
by Paul Eggert Aug. 10, 2017

Aug. 10, 2017

--- NEWS | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/NEWS b/NEWS index 69b6a8b..808959a 100644 --- a/NEWS +++ b/NEWS @@ -2,6 +2,11 @@ News for the tz database Unreleased, experimental changes + Briefly: Namibia switches from +01/+02 to +02 on 2018-04-01. + Turks & Caicos switches from -04 to -05/-04 on 2018-11-04. + A new file tzdata.zi now holds a small text copy of all data. + The zic input format has been regularized slightly. + Changes to future time stamps Namibia will switch from +01 with DST to +02 all year on -- 2.7.4

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Namibia to change time zone/go permanent DST
by Steffen Thorsen Aug. 10, 2017

Aug. 10, 2017

Namibia is going to change their time zone to what is now their DST: https://www.newera.com.na/2017/02/23/namibias-winter-time-might-be-repealed/ This video is from the government decision: https://www.nbc.na/news/na-passes-namibia-time-bill-repealing-1994-namibia-… We have made the assumption so far that they will change their time zone at the same time they would normally start DST, the first Sunday in September: https://www.timeanddate.com/news/time/namibia-new-time-zone.html Best regards, Steffen

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Israel POSIX timezone string error on release 2017b?
by André Domingos Brízido Aug. 8, 2017

Aug. 8, 2017

Hello According to the Linux manual (http://man7.org/linux/man-pages/man5/tzfile.5.html) the last line of the time zone database may contain the POSIX timezone string, which is the case of the files generated by following the instructions in https://www.iana.org/time-zones/repository/tz-link.html I've downloaded the latest release (2017b) and I obtain the following POSIX string for Israel: [/usr/share/zoneinfo]# tail -n 1 Israel IST-2IDT,M3.4.4/26,M10.5.0 But if I understood correctly, the POSIX specification (http://pubs.opengroup.org/onlinepubs/9699919799/) states that the value '26' is out of range. It should be between zero and 24. My linux system does not display the correct timezone if I use the string 'IST-2IDT,M3.4.4/26,M10.5.0' as the contents of /etc/TZ. Best regards Andre Brizido

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[PROPOSED] Improve tzfile.5 formatting and clarity
by Paul Eggert Aug. 7, 2017

Aug. 7, 2017

* tzfile.5: Break out field descriptions into bulleted lists, to make them easier to follow. This does not change the technical content of the spec, just its presentation. --- tzfile.5 | 77 ++++++++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 48 insertions(+), 29 deletions(-) diff --git a/tzfile.5 b/tzfile.5 index 52c5301..b7dc828 100644 --- a/tzfile.5 +++ b/tzfile.5 @@ -10,17 +10,29 @@ tzfile \- time zone information \\$3\*(lq\\$1\*(rq\\$2 .. The time zone information files used by -.IR tzset (3) -begin with the magic characters "TZif" to identify them as -time zone information files, -followed by a character identifying the version of the file's format -(as of 2013, either an ASCII NUL, or '2', or '3') -followed by fifteen bytes containing zeroes reserved for future use, -followed by six four-byte integer values +.BR tzset (3) +are typically found under a directory with a name like +.IR /usr/share/zoneinfo . +These files begin with a 44-byte header containing the following fields: +.IP * 2 +The magic four-byte ASCII sequence +.q "TZif" +identifies the file as a time zone information file. +.IP * +A byte identifying the version of the file's format +(as of 2017, either an ASCII NUL, or +.q "2", +or +.q "3" ). +.IP * +Fifteen bytes containing zeros reserved for future use. +.IP * +Six four-byte integer values written in a standard byte order (the high-order byte of the value is written first). These values are, in order: +.RS .TP .I tzh_ttisgmtcnt The number of UT/local indicators stored in the file. @@ -40,28 +52,30 @@ The number of local time types for which data entries are stored in the file (must not be zero). .TP .I tzh_charcnt -The number of characters of time zone abbreviation strings +The number of bytes of time zone abbreviation strings stored in the file. +.RE .PP -The above header is followed by +The above header is followed by the following fields, whose lengths +vary depend on the contents of the header: +.IP * 2 .I tzh_timecnt four-byte signed integer values sorted in ascending order. These values are written in standard byte order. Each is used as a transition time (as returned by -.IR time (2)) +.BR time (2)) at which the rules for computing local time change. -Next come +.IP * .I tzh_timecnt one-byte unsigned integer values; each one tells which of the different types of local time types described in the file is associated with the time period starting with the same-indexed transition time. -These values serve as indices into an array of -.I ttinfo -structures (with +These values serve as indices into the next field. +.IP * .I tzh_typecnt -entries) that appears next in the file; -these structures are defined as follows: +.I ttinfo +entries, each defined as follows: .in +.5i .sp .nf @@ -87,20 +101,19 @@ gives the number of seconds to be added to UT, tells whether .I tm_isdst should be set by -.I localtime (3) +.BR localtime (3) and .I tt_abbrind -serves as an index into the array of time zone abbreviation characters +serves as an index into the array of time zone abbreviation bytes that follow the .I ttinfo structure(s) in the file. -.PP -Then there are +.IP * .I tzh_leapcnt pairs of four-byte values, written in standard byte order; the first value of each pair gives the nonnegative time (as returned by -.IR time(2)) +.BR time (2)) at which a leap second occurs; the second gives the .I total @@ -109,16 +122,14 @@ starting at the given time. The pairs of values are sorted in ascending order by time. Each transition is for one leap second, either positive or negative; transitions always separated by at least 28 days minus 1 second. -.PP -Then there are +.IP * .I tzh_ttisstdcnt standard/wall indicators, each stored as a one-byte value; they tell whether the transition times associated with local time types were specified as standard time or wall clock time, and are used when a time zone file is used in handling POSIX-style time zone environment variables. -.PP -Finally there are +.IP * .I tzh_ttisgmtcnt UT/local indicators, each stored as a one-byte value; they tell whether the transition times associated with local time types @@ -126,7 +137,9 @@ were specified as UT or local time, and are used when a time zone file is used in handling POSIX-style time zone environment variables. .PP -.I Localtime +The +.BR localtime (3) +function uses the first standard-time .I ttinfo structure in the file @@ -137,11 +150,12 @@ if either .I tzh_timecnt is zero or the time argument is less than the first transition time recorded in the file. -.PP +.SS Version 2 format For version-2-format time zone files, the above header and data are followed by a second header and data, identical in format except that eight bytes are used for each transition time or leap second time. +(Leap second counts remain four bytes.) After the second header and data comes a newline-enclosed, POSIX-TZ-environment-variable-style string for use in handling instants after the last transition time stored in the file @@ -154,7 +168,7 @@ then if a last transition time is in July, the transition's local time type must specify a daylight-saving time abbreviated .q "WEST" that is one hour east of UT. -.PP +.SS Version 3 format For version-3-format time zone files, the POSIX-TZ-style string may use two minor extensions to the POSIX TZ format, as described in .IR newtzset (3). @@ -166,6 +180,11 @@ between daylight saving and standard time. .PP Future changes to the format may append more data. .SH SEE ALSO -newctime(3), newtzset(3), zdump(8), zic(8) +.BR time (2), +.BR localtime (3), +.BR tzset (3), +.BR tzselect (8), +.BR zdump (8), +.BR zic (8) .\" This file is in the public domain, so clarified as of .\" 1996-06-05 by Arthur David Olson. -- 2.7.4

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[PROPOSED] Minor tz-link updates.
by Paul Eggert Aug. 1, 2017

Aug. 1, 2017

* tz-link.htm: Add Noda Time updater. Add a downloading header, and simplify text editor discussion. --- tz-link.htm | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff --git a/tz-link.htm b/tz-link.htm index 803727b..589c781 100644 --- a/tz-link.htm +++ b/tz-link.htm @@ -10,7 +10,7 @@ content="Sources for time zone and daylight saving time data"> <meta name="DC.Creator" content="Eggert, Paul"> <meta name="DC.Contributor" content="Olson, Arthur David"> -<meta name="DC.Date" content="2017-07-08"> +<meta name="DC.Date" content="2017-08-01"> <meta name="DC.Description" content="Sources of information about time zones and daylight saving time"> <meta name="DC.Identifier" @@ -105,6 +105,7 @@ Universal Time</a> (<abbr>UTC</abbr>). The database also records when daylight saving time was in use, along with some time zone abbreviations such as <abbr>EST</abbr> for Eastern Standard Time in the <abbr>US</abbr>. +<h2 id="download">Downloading the <code><abbr>tz</abbr></code> database</h2> The following <a href="https://en.wikipedia.org/wiki/Unix_shell">shell</a> commands download @@ -196,9 +197,10 @@ title="International Components for Unicode">ICU</abbr></a>, <a href="https://developer.ibm.com/javasdk/support/dst/jtzu/"><abbr>IBM</abbr></a> and <a href="http://www.oracle.com/technetwork/java/javase/tzupdater-readme-136440.html">Oracle</a> -Java, <a href="http://www.joda.org/joda-time/tz_update.html">Joda-Time</a>, +Java, <a href="http://www.joda.org/joda-time/tz_update.html">Joda-Time</a>, <a +href="https://dev.mysql.com/doc/refman/en/time-zone-support.html">MySQL</a>, and <a -href="https://dev.mysql.com/doc/refman/en/time-zone-support.html">MySQL</a>. +href="http://nodatime.org/userguide/tzdb">Noda Time</a> (see below). Sources for the <code><abbr>tz</abbr></code> database are <a href="https://en.wikipedia.org/wiki/UTF-8"><abbr @@ -209,14 +211,11 @@ title="linefeed">LF</abbr></a>, which can be modified by common text editors such as <a href="https://www.gnu.org/software/emacs/">GNU Emacs</a>, <a href="https://wiki.gnome.org/Apps/Gedit">gedit</a>, and -<a href="http://www.vim.org">vim</a>. One -editor has a package to simplify editing further: -<ul> -<li><a href="https://packagecontrol.io/packages/zoneinfo">Sublime -zoneinfo</a> is a <a href="http://www.sublimetext.com">Sublime -Text</a> package for syntax highlighting <code><abbr>tz</abbr></code> -source files.</li> -</ul> +<a href="http://www.vim.org">vim</a>. The <a +href="http://www.sublimetext.com">Sublime Text</a> editor has +a <a href="https://packagecontrol.io/packages/zoneinfo">Sublime +zoneinfo</a> package to simplify editing further. + For further information about updates, please see <a href="https://tools.ietf.org/html/rfc6557">Procedures for -- 2.7.4

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[PROPOSED] Detroit did not observe DST in 1967
by Paul Eggert July 27, 2017

July 27, 2017

* NEWS: Document this. * northamerica (Detroit): Remove bogus 1967 rules that were taken from Shanks. --- NEWS | 2 ++ northamerica | 15 +++++++++++++-- 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/NEWS b/NEWS index 64d5c91..93633a5 100644 --- a/NEWS +++ b/NEWS @@ -4,6 +4,8 @@ Unreleased, experimental changes Changes to past time stamps + Detroit did not observe DST in 1967. + Use railway time for Asia/Kolkata before 1941, by switching to Madras local time (UT +052110) in 1870, then to IST (UT +0530) in 1906. Also, treat 1941-2's +0630 as DST, like 1942-5. diff --git a/northamerica b/northamerica index 651681d..b42aeb4 100644 --- a/northamerica +++ b/northamerica @@ -1040,12 +1040,23 @@ Zone America/Kentucky/Monticello -5:39:24 - LMT 1883 Nov 18 12:20:36 # one hour in 1914." This change is not in Shanks. We have no more # info, so omit this for now. # +# From Paul Eggert (2017-07-26): +# Although Shanks says Detroit observed DST in 1967 from 06-14 00:01 +# until 10-29 00:01, I now see multiple reports that this is incorrect. +# For example, according to a 50-year anniversary report about the 1967 +# Detroit riots and a major-league doubleheader on 1967-07-23, "By the time +# the last fly ball of the doubleheader settled into the glove of leftfielder +# Lenny Green, it was after 7 p.m. Detroit did not observe daylight saving +# time, so light was already starting to fail. Twilight was made even deeper +# by billowing columns of smoke that ascended in an unbroken wall north of the +# ballpark." See: Dow B. Detroit '67: As violence unfolded, Tigers played two +# at home vs. Yankees. Detroit Free Press 2017-07-23. +# http://www.freep.com/story/sports/mlb/tigers/2017/07/23/detroit-tigers-1967… +# # Most of Michigan observed DST from 1973 on, but was a bit late in 1975. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER Rule Detroit 1948 only - Apr lastSun 2:00 1:00 D Rule Detroit 1948 only - Sep lastSun 2:00 0 S -Rule Detroit 1967 only - Jun 14 2:00 1:00 D -Rule Detroit 1967 only - Oct lastSun 2:00 0 S # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone America/Detroit -5:32:11 - LMT 1905 -6:00 - CST 1915 May 15 2:00 -- 2.13.3

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Re: [tz] libc-2.25.90.pot
by Paul Eggert July 20, 2017

July 20, 2017

On 07/20/2017 07:57 AM, Siddhesh Poyarekar wrote: > Oh I meant PRIdLINENO, not PRIdMAX. I suppose using PRIdMAX directly > might work since gettext seems to recognize the other PRI* macros. Yes, PRIdMAX should work. The zic.c code uses the macro (as opposed to just %jd) to be portable to pre-C99 libraries. I installed the attached patch into the upstream tzdb sources; the zic.c part of it should work for glibc too. Thanks for reporting the problem.

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[PROPOSED] Use more up-to-date citation for leap seconds
by Paul Eggert July 18, 2017

July 18, 2017

* leapseconds.awk: Cite Levine 2016 instead of Quinn 1991. --- leapseconds.awk | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/leapseconds.awk b/leapseconds.awk index 405ce3a..66eb64d 100644 --- a/leapseconds.awk +++ b/leapseconds.awk @@ -17,11 +17,9 @@ BEGIN { print "# The International Earth Rotation and Reference Systems Service" print "# periodically uses leap seconds to keep UTC to within 0.9 s of UT1" print "# (which measures the true angular orientation of the earth in space); see" - print "# Terry J Quinn, The BIPM and the accurate measure of time," - print "# Proc IEEE 79, 7 (July 1991), 894-905 <http://dx.doi.org/10.1109/5.84965>," - print "# reprinted in: Hackman C, Sullivan DB (eds), Time and frequency measurement," - print "# American Association of Physics Teachers (1996)," - print "# <http://tf.nist.gov/general/pdf/1168.pdf>, 75-86." + print "# Levine J. Coordinated Universal Time and the leap second." + print "# URSI Radio Sci Bull. 2016;89(4):30-6. doi:10.23919/URSIRSB.2016.7909995" + print "# http://ieeexplore.ieee.org/document/7909995/" print "# There were no leap seconds before 1972, because the official mechanism" print "# accounting for the discrepancy between atomic time and the earth's rotation" print "# did not exist until the early 1970s." -- 2.7.4

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Pedantic correction to Theory regarding size of time zone names
by Howard Hinnant July 16, 2017

July 16, 2017

Line 91 of Theory: https://github.com/eggert/tz/blob/master/Theory#L91 reads: > A file name component must not exceed 14 characters … I found one exception to this rule: The Link: Canada/East-Saskatchewan in backward. East-Saskatchewan is 17 characters. I recommend simply changing the 14 to 17. Howard

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Unix time_t hits 1.5Gs early Friday UTC
by Brian Inglis July 14, 2017

July 14, 2017

Unix time_t will hit 1 500 000 000 at 2017 Jul 14 Fri 02:40:00+0000 which is Thursday evening in North America: $ for city in Vancouver Edmonton Regina Winnipeg Toronto Halifax St_Johns; do TZ=America/$city date -d@1500000000 +%c\ %Z; done 2017 Jul 13 Thu 19:40:00 PDT 2017 Jul 13 Thu 20:40:00 MDT 2017 Jul 13 Thu 20:40:00 CST 2017 Jul 13 Thu 21:40:00 CDT 2017 Jul 13 Thu 22:40:00 EDT 2017 Jul 13 Thu 23:40:00 ADT 2017 Jul 14 Fri 00:10:00 NDT and on some other time scales, which may not be aligned to UTC: $ gpstime.sh @1500000000 2017 Jul 14 Fri 02:40:00+0000 JD 2457948.611111 MJD 57948.111111 ToD 9599 NTP 3708988800 Unix 1500000000 TAI-UTC 37 TAI-GPS 19 GPS-UTC 18 GPS We 1957 Cy 1 Wn 933 Wa 165 ToW 441618 DoW 5 ToD 9618 As usual there will be some Europeans staying up late to celebrate and party. Unix time won't hit 1.5Gis until: $ gpstime.sh @`bc <<< 2^30*3/2` 2021 Jan 14 Thu 08:25:36+0000 JD 2459228.851111 MJD 59228.351111 ToD 30336 NTP 3819601536 Unix 1610612736 TAI-UTC 37 TAI-GPS 19 GPS-UTC 18 GPS We 2140 Cy 2 Wn 92 Wa 92 ToW 375954 DoW 4 ToD 30354 and it will be a while before it hits 2Gs: $ gpstime.sh @2000000000 2033 May 18 Wed 03:33:20+0000 JD 2463735.648148 MJD 63735.148148 ToD 12799 NTP 4208988800 Unix 2000000000 TAI-UTC 37 TAI-GPS 19 GPS-UTC 18 GPS We 2784 Cy 2 Wn 736 Wa 224 ToW 272018 DoW 3 ToD 12818 -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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Use GST abbreviation for Asia/Dubai, Asia/Muscat
by Mohamed Akram July 14, 2017

July 14, 2017

I noticed Asia/Dubai and Asia/Muscat currently use +04, but there is an existing abbreviation (GST - Gulf Standard Time).

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Etc/GMT timezone offsets are inverted
by Pedro A. López-Valencia July 11, 2017

July 11, 2017

I just noticed that all GMT+- timezones are inverted so that GMT+5 is really GMT-5. This applies to all GMT-offset timezone definitions. -- https://about.me/palopezv

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IERS Bulletin C54
by Michael Deckers July 11, 2017

July 11, 2017

The IERS has issued Bulletin C54 which assures that no leap second will occur near 2018-01-01. Interestingly, the issue date 2017-07-06 in the txt version at [https://datacenter.iers.org/eop/-/somos/5Rgv/getTX/16/bulletinc-054.txt] differs from the issue date 2017-07-09 in the xml version at [https://datacenter.iers.org/eop/-/somos/5Rgv/latestXL/16/bulletinc-054.txt/…] Michael Deckers. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

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backzone/Europe/Guernsey
by Michael Deckers July 10, 2017

July 10, 2017

For the connoisseurs of olde time stamps: The "LMT location" for backzone/Europe/Guernsey is given as "49.27N -2.33E" -- seemingly in degrees and decimal fractions of degrees. But the point ( +49.27°, -2.33° ) = ( +49°16′12″, -002°19′48″ ) is in open waters about 15 km south of Guernsey and east of Sark in the Channel. The point ( +49°27′, -002°33′ ), however, is in St Peter Port on the island, so that arc minutes and not hundredths of degrees must be meant. This also agrees with zone.tab. Hence: -# LMT Location - 49.27N -2.33E - St.Peter Port +# LMT Location - 49°27′N -2°33′E - St.Peter Port -Zone Europe/Guernsey -0:09:19 - LMT 1913 Jun 18 +Zone Europe/Guernsey -0:10:12 - LMT 1913 Jun 18 Michael Deckers. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

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Re: [tz] TZ & AIX
by Paul Eggert July 8, 2017

July 8, 2017

Jorge Fábregas wrote: > https://www.ibm.com/developerworks/aix/library/au-aix-olson-time-zone/index… Thanks for the heads-up. I installed the attached.

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Orillia's 1912 DST pops up again in Toronto Star
by Paul Eggert July 8, 2017

July 8, 2017

Today's Toronto Star reports on the two-week daylight saving time interlude in Orillia, Ontario. Today's article doesn't mention the same newspaper's 1997-10-14 article on the same topic, and it's not clear what's new this time around. Still, the story is amusingly told. Proposed patch attached.

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DST in the (odd) news
by Arthur David Olson July 7, 2017

July 7, 2017

"Alarm clock removed from family's home after 14 years of daily beeping" "Over the years, it beeped at 6.50pm or 7.50pm each day, depending on whether Daylight [Saving] Time was in place." https://www.theguardian.com/us-news/2017/jul/07/alarm-clock-wall-pennsylvan… @dashdashado

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