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   4 # This code is free software; you can redistribute it and/or modify it
   5 # under the terms of the GNU General Public License version 2 only, as
   6 # published by the Free Software Foundation.  Oracle designates this
   7 # particular file as subject to the "Classpath" exception as provided
   8 # by Oracle in the LICENSE file that accompanied this code.
   9 #
  10 # This code is distributed in the hope that it will be useful, but WITHOUT
  11 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13 # version 2 for more details (a copy is included in the LICENSE file that
  14 # accompanied this code).
  15 #
  16 # You should have received a copy of the GNU General Public License version
  17 # 2 along with this work; if not, write to the Free Software Foundation,
  18 # Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19 #
  20 # Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21 # or visit www.oracle.com if you need additional information or have any
  22 # questions.
  23 #


  24 # This file is in the public domain, so clarified as of
  25 # 2009-05-17 by Arthur David Olson.
  26 
  27 # also includes Central America and the Caribbean
  28 
  29 # This file is by no means authoritative; if you think you know better,
  30 # go ahead and edit the file (and please send any changes to
  31 # tz@iana.org for general use in the future).  For more, please see
  32 # the file CONTRIBUTING in the tz distribution.
  33 
  34 # From Paul Eggert (1999-03-22):
  35 # A reliable and entertaining source about time zones is
  36 # Derek Howse, Greenwich time and longitude, Philip Wilson Publishers (1997).
  37 
  38 ###############################################################################
  39 
  40 # United States
  41 
  42 # From Paul Eggert (1999-03-31):
  43 # Howse writes (pp 121-125) that time zones were invented by


  54 # work in the US was William Frederick Allen - railway engineer,
  55 # managing editor of the Travelers' Guide, and secretary of the
  56 # General Time Convention, a railway standardization group.  Allen
  57 # spent months in dialogs with scientific and railway leaders,
  58 # developed a workable plan to institute time zones, and presented it
  59 # to the General Time Convention on 1883-04-11, saying that his plan
  60 # meant "local time would be practically abolished" - a plus for
  61 # railway scheduling.  By the next convention on 1883-10-11 nearly all
  62 # railroads had agreed and it took effect on 1883-11-18.  That Sunday
  63 # was called the "day of two noons", as some locations observed noon
  64 # twice.  Allen witnessed the transition in New York City, writing:
  65 #
  66 #   I heard the bells of St. Paul's strike on the old time.  Four
  67 #   minutes later, obedient to the electrical signal from the Naval
  68 #   Observatory ... the time-ball made its rapid descent, the chimes
  69 #   of old Trinity rang twelve measured strokes, and local time was
  70 #   abandoned, probably forever.
  71 #
  72 # Most of the US soon followed suit.  See:
  73 # Bartky IR. The adoption of standard time. Technol Cult 1989 Jan;30(1):25-56.
  74 # http://dx.doi.org/10.2307/3105430
  75 
  76 # From Paul Eggert (2005-04-16):
  77 # That 1883 transition occurred at 12:00 new time, not at 12:00 old time.
  78 # See p 46 of David Prerau, Seize the daylight, Thunder's Mouth Press (2005).
  79 
  80 # From Paul Eggert (2006-03-22):
  81 # A good source for time zone historical data in the US is
  82 # Thomas G. Shanks, The American Atlas (5th edition),
  83 # San Diego: ACS Publications, Inc. (1991).
  84 # Make sure you have the errata sheet; the book is somewhat useless without it.
  85 # It is the source for most of the pre-1991 US entries below.
  86 
  87 # From Paul Eggert (2001-03-06):
  88 # Daylight Saving Time was first suggested as a joke by Benjamin Franklin
  89 # in his whimsical essay "An Economical Project for Diminishing the Cost
  90 # of Light" published in the Journal de Paris (1784-04-26).
  91 # Not everyone is happy with the results:
  92 #
  93 #       I don't really care how time is reckoned so long as there is some
  94 #       agreement about it, but I object to being told that I am saving


 443 # http://www.bismarcktribune.com/news/local/article_1eb1b588-c758-11df-b472-001cc4c03286.html
 444 
 445 # From Andy Lipscomb (2011-01-24):
 446 # ...according to the Census Bureau, the largest city is Beulah (although
 447 # it's commonly referred to as Beulah-Hazen, with Hazen being the next
 448 # largest city in Mercer County).  Google Maps places Beulah's city hall
 449 # at 47° 15' 51" N, 101° 46' 40" W, which yields an offset of 6h47'07".
 450 
 451 Zone America/North_Dakota/Beulah -6:47:07 - LMT 1883 Nov 18 12:12:53
 452                         -7:00   US      M%sT    2010 Nov  7  2:00
 453                         -6:00   US      C%sT
 454 
 455 # US mountain time, represented by Denver
 456 #
 457 # Colorado, far western Kansas, Montana, western
 458 # Nebraska, Nevada border (Jackpot, Owyhee, and Mountain City),
 459 # New Mexico, southwestern North Dakota,
 460 # western South Dakota, far western Texas (El Paso County, Hudspeth County,
 461 # and Pine Springs and Nickel Creek in Culberson County), Utah, Wyoming
 462 #













 463 # Rule  NAME    FROM    TO      TYPE    IN      ON      AT      SAVE    LETTER
 464 Rule    Denver  1920    1921    -       Mar     lastSun 2:00    1:00    D
 465 Rule    Denver  1920    only    -       Oct     lastSun 2:00    0       S
 466 Rule    Denver  1921    only    -       May     22      2:00    0       S
 467 Rule    Denver  1965    1966    -       Apr     lastSun 2:00    1:00    D
 468 Rule    Denver  1965    1966    -       Oct     lastSun 2:00    0       S
 469 # Zone  NAME            GMTOFF  RULES   FORMAT  [UNTIL]
 470 Zone America/Denver     -6:59:56 -      LMT     1883 Nov 18 12:00:04
 471                         -7:00   US      M%sT    1920
 472                         -7:00   Denver  M%sT    1942
 473                         -7:00   US      M%sT    1946
 474                         -7:00   Denver  M%sT    1967
 475                         -7:00   US      M%sT
 476 
 477 # US Pacific time, represented by Los Angeles
 478 #
 479 # California, northern Idaho (Benewah, Bonner, Boundary, Clearwater,
 480 # Kootenai, Latah, Lewis, Nez Perce, and Shoshone counties, Idaho county
 481 # north of the Salmon River, and the towns of Burgdorf and Warren),
 482 # Nevada (except West Wendover), Oregon (except the northern ¾ of


 712 # Seventeenth Legislature: Regular Session 1933," available (as of
 713 # 2011-01-19) at American University's Pence Law Library. Page 85: "Act
 714 # 90...At 2 o'clock ante meridian of the last Sunday in April of each
 715 # year, the standard time of this Territory shall be advanced one
 716 # hour...This Act shall take effect upon its approval. Approved this 26th
 717 # day of April, A. D. 1933. LAWRENCE M JUDD, Governor of the Territory of
 718 # Hawaii." Page 172: "Act 163...Act 90 of the Session Laws of 1933 is
 719 # hereby repealed...This Act shall take effect upon its approval, upon
 720 # which date the standard time of this Territory shall be restored to
 721 # that existing immediately prior to the taking effect of said Act 90.
 722 # Approved this 21st day of May, A. D. 1933. LAWRENCE M. JUDD, Governor
 723 # of the Territory of Hawaii."
 724 #
 725 # Note that 1933-05-21 was a Sunday.
 726 # We're left to guess the time of day when Act 163 was approved; guess noon.
 727 
 728 # Zone  NAME            GMTOFF  RULES   FORMAT  [UNTIL]
 729 Zone Pacific/Honolulu   -10:31:26 -     LMT     1896 Jan 13 12:00
 730                         -10:30  -       HST     1933 Apr 30  2:00
 731                         -10:30  1:00    HDT     1933 May 21 12:00
 732                         -10:30  -       HST     1942 Feb  9  2:00
 733                         -10:30  1:00    HDT     1945 Sep 30  2:00
 734                         -10:30  -       HST     1947 Jun  8  2:00
 735                         -10:00  -       HST
 736 
 737 # Now we turn to US areas that have diverged from the consensus since 1970.
 738 
 739 # Arizona mostly uses MST.
 740 
 741 # From Paul Eggert (2002-10-20):
 742 #
 743 # The information in the rest of this paragraph is derived from the
 744 # Daylight Saving Time web page
 745 # <http://www.dlapr.lib.az.us/links/daylight.htm> (2002-01-23)
 746 # maintained by the Arizona State Library, Archives and Public Records.
 747 # Between 1944-01-01 and 1944-04-01 the State of Arizona used standard
 748 # time, but by federal law railroads, airlines, bus lines, military
 749 # personnel, and some engaged in interstate commerce continued to
 750 # observe war (i.e., daylight saving) time.  The 1944-03-17 Phoenix
 751 # Gazette says that was the date the law changed, and that 04-01 was
 752 # the date the state's clocks would change.  In 1945 the State of
 753 # Arizona used standard time all year, again with exceptions only as
 754 # mandated by federal law.  Arizona observed DST in 1967, but Arizona




   4 # This code is free software; you can redistribute it and/or modify it
   5 # under the terms of the GNU General Public License version 2 only, as
   6 # published by the Free Software Foundation.  Oracle designates this
   7 # particular file as subject to the "Classpath" exception as provided
   8 # by Oracle in the LICENSE file that accompanied this code.
   9 #
  10 # This code is distributed in the hope that it will be useful, but WITHOUT
  11 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13 # version 2 for more details (a copy is included in the LICENSE file that
  14 # accompanied this code).
  15 #
  16 # You should have received a copy of the GNU General Public License version
  17 # 2 along with this work; if not, write to the Free Software Foundation,
  18 # Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19 #
  20 # Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21 # or visit www.oracle.com if you need additional information or have any
  22 # questions.
  23 #
  24 # tzdb data for North and Central America and environs
  25 
  26 # This file is in the public domain, so clarified as of
  27 # 2009-05-17 by Arthur David Olson.
  28 
  29 # also includes Central America and the Caribbean
  30 
  31 # This file is by no means authoritative; if you think you know better,
  32 # go ahead and edit the file (and please send any changes to
  33 # tz@iana.org for general use in the future).  For more, please see
  34 # the file CONTRIBUTING in the tz distribution.
  35 
  36 # From Paul Eggert (1999-03-22):
  37 # A reliable and entertaining source about time zones is
  38 # Derek Howse, Greenwich time and longitude, Philip Wilson Publishers (1997).
  39 
  40 ###############################################################################
  41 
  42 # United States
  43 
  44 # From Paul Eggert (1999-03-31):
  45 # Howse writes (pp 121-125) that time zones were invented by


  56 # work in the US was William Frederick Allen - railway engineer,
  57 # managing editor of the Travelers' Guide, and secretary of the
  58 # General Time Convention, a railway standardization group.  Allen
  59 # spent months in dialogs with scientific and railway leaders,
  60 # developed a workable plan to institute time zones, and presented it
  61 # to the General Time Convention on 1883-04-11, saying that his plan
  62 # meant "local time would be practically abolished" - a plus for
  63 # railway scheduling.  By the next convention on 1883-10-11 nearly all
  64 # railroads had agreed and it took effect on 1883-11-18.  That Sunday
  65 # was called the "day of two noons", as some locations observed noon
  66 # twice.  Allen witnessed the transition in New York City, writing:
  67 #
  68 #   I heard the bells of St. Paul's strike on the old time.  Four
  69 #   minutes later, obedient to the electrical signal from the Naval
  70 #   Observatory ... the time-ball made its rapid descent, the chimes
  71 #   of old Trinity rang twelve measured strokes, and local time was
  72 #   abandoned, probably forever.
  73 #
  74 # Most of the US soon followed suit.  See:
  75 # Bartky IR. The adoption of standard time. Technol Cult 1989 Jan;30(1):25-56.
  76 # https://dx.doi.org/10.2307/3105430
  77 
  78 # From Paul Eggert (2005-04-16):
  79 # That 1883 transition occurred at 12:00 new time, not at 12:00 old time.
  80 # See p 46 of David Prerau, Seize the daylight, Thunder's Mouth Press (2005).
  81 
  82 # From Paul Eggert (2006-03-22):
  83 # A good source for time zone historical data in the US is
  84 # Thomas G. Shanks, The American Atlas (5th edition),
  85 # San Diego: ACS Publications, Inc. (1991).
  86 # Make sure you have the errata sheet; the book is somewhat useless without it.
  87 # It is the source for most of the pre-1991 US entries below.
  88 
  89 # From Paul Eggert (2001-03-06):
  90 # Daylight Saving Time was first suggested as a joke by Benjamin Franklin
  91 # in his whimsical essay "An Economical Project for Diminishing the Cost
  92 # of Light" published in the Journal de Paris (1784-04-26).
  93 # Not everyone is happy with the results:
  94 #
  95 #       I don't really care how time is reckoned so long as there is some
  96 #       agreement about it, but I object to being told that I am saving


 445 # http://www.bismarcktribune.com/news/local/article_1eb1b588-c758-11df-b472-001cc4c03286.html
 446 
 447 # From Andy Lipscomb (2011-01-24):
 448 # ...according to the Census Bureau, the largest city is Beulah (although
 449 # it's commonly referred to as Beulah-Hazen, with Hazen being the next
 450 # largest city in Mercer County).  Google Maps places Beulah's city hall
 451 # at 47° 15' 51" N, 101° 46' 40" W, which yields an offset of 6h47'07".
 452 
 453 Zone America/North_Dakota/Beulah -6:47:07 - LMT 1883 Nov 18 12:12:53
 454                         -7:00   US      M%sT    2010 Nov  7  2:00
 455                         -6:00   US      C%sT
 456 
 457 # US mountain time, represented by Denver
 458 #
 459 # Colorado, far western Kansas, Montana, western
 460 # Nebraska, Nevada border (Jackpot, Owyhee, and Mountain City),
 461 # New Mexico, southwestern North Dakota,
 462 # western South Dakota, far western Texas (El Paso County, Hudspeth County,
 463 # and Pine Springs and Nickel Creek in Culberson County), Utah, Wyoming
 464 #
 465 # From Paul Eggert (2018-10-25):
 466 # On 1921-03-04 federal law placed all of Texas into the central time zone.
 467 # However, El Paso ignored the law for decades and continued to observe
 468 # mountain time, on the grounds that that's what they had always done
 469 # and they weren't about to let the federal government tell them what to do.
 470 # Eventually the federal government gave in and changed the law on
 471 # 1970-04-10 to match what El Paso was actually doing.  Although
 472 # that's slightly after our 1970 cutoff, there is no need to create a
 473 # separate zone for El Paso since they were ignoring the law anyway.  See:
 474 # Long T. El Pasoans were time rebels, fought to stay in Mountain zone.
 475 # El Paso Times. 2018-10-24 06:40 -06.
 476 # https://www.elpasotimes.com/story/news/local/el-paso/2018/10/24/el-pasoans-were-time-rebels-fought-stay-mountain-zone/1744509002/
 477 #
 478 # Rule  NAME    FROM    TO      TYPE    IN      ON      AT      SAVE    LETTER
 479 Rule    Denver  1920    1921    -       Mar     lastSun 2:00    1:00    D
 480 Rule    Denver  1920    only    -       Oct     lastSun 2:00    0       S
 481 Rule    Denver  1921    only    -       May     22      2:00    0       S
 482 Rule    Denver  1965    1966    -       Apr     lastSun 2:00    1:00    D
 483 Rule    Denver  1965    1966    -       Oct     lastSun 2:00    0       S
 484 # Zone  NAME            GMTOFF  RULES   FORMAT  [UNTIL]
 485 Zone America/Denver     -6:59:56 -      LMT     1883 Nov 18 12:00:04
 486                         -7:00   US      M%sT    1920
 487                         -7:00   Denver  M%sT    1942
 488                         -7:00   US      M%sT    1946
 489                         -7:00   Denver  M%sT    1967
 490                         -7:00   US      M%sT
 491 
 492 # US Pacific time, represented by Los Angeles
 493 #
 494 # California, northern Idaho (Benewah, Bonner, Boundary, Clearwater,
 495 # Kootenai, Latah, Lewis, Nez Perce, and Shoshone counties, Idaho county
 496 # north of the Salmon River, and the towns of Burgdorf and Warren),
 497 # Nevada (except West Wendover), Oregon (except the northern ¾ of


 727 # Seventeenth Legislature: Regular Session 1933," available (as of
 728 # 2011-01-19) at American University's Pence Law Library. Page 85: "Act
 729 # 90...At 2 o'clock ante meridian of the last Sunday in April of each
 730 # year, the standard time of this Territory shall be advanced one
 731 # hour...This Act shall take effect upon its approval. Approved this 26th
 732 # day of April, A. D. 1933. LAWRENCE M JUDD, Governor of the Territory of
 733 # Hawaii." Page 172: "Act 163...Act 90 of the Session Laws of 1933 is
 734 # hereby repealed...This Act shall take effect upon its approval, upon
 735 # which date the standard time of this Territory shall be restored to
 736 # that existing immediately prior to the taking effect of said Act 90.
 737 # Approved this 21st day of May, A. D. 1933. LAWRENCE M. JUDD, Governor
 738 # of the Territory of Hawaii."
 739 #
 740 # Note that 1933-05-21 was a Sunday.
 741 # We're left to guess the time of day when Act 163 was approved; guess noon.
 742 
 743 # Zone  NAME            GMTOFF  RULES   FORMAT  [UNTIL]
 744 Zone Pacific/Honolulu   -10:31:26 -     LMT     1896 Jan 13 12:00
 745                         -10:30  -       HST     1933 Apr 30  2:00
 746                         -10:30  1:00    HDT     1933 May 21 12:00
 747                         -10:30  US      H%sT    1947 Jun  8  2:00


 748                         -10:00  -       HST
 749 
 750 # Now we turn to US areas that have diverged from the consensus since 1970.
 751 
 752 # Arizona mostly uses MST.
 753 
 754 # From Paul Eggert (2002-10-20):
 755 #
 756 # The information in the rest of this paragraph is derived from the
 757 # Daylight Saving Time web page
 758 # <http://www.dlapr.lib.az.us/links/daylight.htm> (2002-01-23)
 759 # maintained by the Arizona State Library, Archives and Public Records.
 760 # Between 1944-01-01 and 1944-04-01 the State of Arizona used standard
 761 # time, but by federal law railroads, airlines, bus lines, military
 762 # personnel, and some engaged in interstate commerce continued to
 763 # observe war (i.e., daylight saving) time.  The 1944-03-17 Phoenix
 764 # Gazette says that was the date the law changed, and that 04-01 was
 765 # the date the state's clocks would change.  In 1945 the State of
 766 # Arizona used standard time all year, again with exceptions only as
 767 # mandated by federal law.  Arizona observed DST in 1967, but Arizona


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