December 1993 - tz - lists.iana.org

Re: Iceland's timezone
by Adam David 09 Dec '93

09 Dec '93

> # time the norsemen first settled Iceland. The first day of winter is always > # Saturday, but is not dependent on the Julian or Gregorian calendars. I will try and find a general rule for this, but it may take awhile. > # We go with the Almanak, except for two claims from Shanks: > # 1. In 1968 standard time wasn't switched to GMT until Oct 27; > # this affects only the time zone name and dst flag. I wonder if this one is such a good idea. Here is the actual quote from the almanak (paraphrased): In the year 1968 "summer time" was finally made standard time in Iceland by law number 6 from April 5th that year. The change was made on April 7th at 2:00 GMT and the clock was adjusted forwards by one hour. Clock time in Iceland has since then been on GMT the whole year round. Of course, both Shanks and the Almanak have the same actual time offset for summer 1968, but technically it is the Almanak that is correct. Shanks chooses October 27th as the transition time because that is when the end of the summer time would otherwise have been (by the previous general rule). -- Adam David <adam(a)veda.is>

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Iceland's timezone
by yata!eggert＠twinsun.com 09 Dec '93

09 Dec '93

Thanks for looking up the U of Iceland Almanak. Here's how I translated what you wrote into tzfile format; I'll include this in the next set of revisions that I propose to ado. # Iceland # # From Adam David <adam(a)veda.is> (November 6, 1993): # The name of the timezone in Iceland for system / mail / news purposes is GMT. # # (December 5, 1993): # This material is paraphrased from the 1988 edition of the University of # Iceland Almanak. # # From January 1st, 1908 the whole of Iceland was standardised at 1 hour # behind GMT. Previously, local mean solar time was used in different parts # of Iceland, the almanak had been based on Reykjavik mean solar time which # was 1 hour and 28 minutes behind GMT. # # "first day of winter" referred to [below] means the first day of the 26 weeks # of winter, according to the old icelandic calendar that dates back to the # time the norsemen first settled Iceland. The first day of winter is always # Saturday, but is not dependent on the Julian or Gregorian calendars. # # From Paul Eggert <eggert(a)twinsun.com> (December 9, 1993): # The Iceland Almanak, Shanks and Whitman disagree on many points. # We go with the Almanak, except for two claims from Shanks: # 1. In 1968 standard time wasn't switched to GMT until Oct 27; # this affects only the time zone name and dst flag. # 2. Reykavik was -1:28 from 1837 to 1908, local mean time before that. # # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Iceland 1908 only - Jan 1 0:00 0 S Rule Iceland 1917 1918 - Feb 19 23:00 1:00 D Rule Iceland 1917 only - Oct 21 1:00 0 S Rule Iceland 1918 only - Nov 16 1:00 0 S Rule Iceland 1939 only - Apr 29 23:00 1:00 D Rule Iceland 1939 only - Nov 29 2:00 0 S Rule Iceland 1940 only - Feb 25 2:00 1:00 D Rule Iceland 1940 only - Nov 3 2:00 0 S Rule Iceland 1941 only - Mar 2 1:00s 1:00 D Rule Iceland 1941 only - Nov 2 1:00s 0 S Rule Iceland 1942 only - Mar 8 1:00s 1:00 D Rule Iceland 1942 only - Oct 25 1:00s 0 S # 1943-1946 - first Sunday in March until first Sunday in winter Rule Iceland 1943 1946 - Mar Sun>=1 1:00s 1:00 D Rule Iceland 1943 1948 - Oct Sun>=22 1:00s 0 S # 1947-1967 - first Sunday in April until first Sunday in winter Rule Iceland 1947 1968 - Apr Sun>=1 1:00s 1:00 D # 1949 Oct transition delayed by 1 week Rule Iceland 1949 only - Oct 30 1:00s 0 S Rule Iceland 1950 1966 - Oct Sun>=22 1:00s 0 S Rule Iceland 1967 only - Oct 29 1:00s 0 S # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Atlantic/Reykjavik -1:27:24 - LMT 1837 -1:28 - RMT 1908 # Reykjavik Mean Time -1:00 Iceland I%sT 1968 Oct 27 1:00s 0:00 - GMT

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Re: Iceland's timezone
by Adam David 06 Dec '93

06 Dec '93

Sorry about the delay getting back with this information. > I'm working on a rewrite of `europe' with a large set of historical > data. My current draft (see below) claims that Iceland changed its > timezone in 1968. I've taken this claim from Thomas G. Shanks, The > international atlas (3rd edition), San Diego: ACS Publications, Inc. > (1991). If you have some better data, please let me know. In a way, there was a timezone change in 1968, where the summertime change was applied during the spring, and became the all-year-round time, and there have been no changes since then, not for DST or any other reason. When looking back to previous years when there was DST, icelanders tend to refer to the concept of "winter time", as the summer time had the same offset as the present all-year-round time. This is why I was led to believe that no timezone change had taken place in 1968. > It would be nice to know what time zone abbreviations were used before > 1968, since Shanks doesn't say. In the following table I've made up > the names `IST', `IDT', `RMT', and `LMT' for Iceland Standard Time, > Iceland Daylight Time, Reykjavik Mean Time, and Local Mean Time > respectively. I have no details of any abbreviations, sorry. > # From Shanks (1991): > # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S > Rule Iceland 1908 only - Jan 1 0:00 0 S > Rule Iceland 1917 1918 - Feb 20 2:00 1:00 D > Rule Iceland 1917 only - Oct 25 2:00 0 S > Rule Iceland 1918 1919 - Nov 15 2:00 0 S > Rule Iceland 1919 only - Feb 19 2:00 1:00 D > Rule Iceland 1921 only - Mar 19 2:00 1:00 D > Rule Iceland 1921 only - Jun 22 2:00 0 S > Rule Iceland 1941 1942 - Mar Sat>=1 2:00 1:00 D > Rule Iceland 1941 1942 - Jul 2 2:00 0 S > Rule Iceland 1943 1946 - Mar Sun>=1 2:00 1:00 D > Rule Iceland 1943 1948 - Oct Sun>=22 2:00 0 S > Rule Iceland 1947 1962 - Apr Sun>=1 2:00 1:00 D > Rule Iceland 1949 only - Oct 30 2:00 0 S > Rule Iceland 1950 only - Oct 22 2:00 0 S > # From Paul Eggert <eggert(a)twinsun.com> (November 10, 1993): > # Shanks's ``1953 Oct 26'' is probably a typo for Oct 25. > # Likewise, correct Shanks's ``1961 Oct 22'' to Oct 29. > Rule Iceland 1951 1967 - Oct Sun>=23 1:00s 0 S > Rule Iceland 1963 1968 - Apr Sun>=1 1:00s 1:00 D > # Zone NAME GMTOFF RULES/SAVE FORMAT [UNTIL] > Zone Atlantic/Iceland/Reykjavik -1:27:24 - LMT 1837 Jan 1 > -1:28 - RMT 1908 Jan 1 > -1:00 Iceland I%sT 1968 Oct 27 1:00s > 0:00 - GMT > # This link is for backward compatibility with the old naming convention. > Link Atlantic/Iceland/Reykjavik Iceland I don't feel up to messing with this table and submitting a corrected version. Here I copy a list of periods when summertime was active, and explanatory text. This material is paraphrased from the 1988 edition of the University of Iceland Almanak. >From January 1st, 1908 the whole of Iceland was standardised at 1 hour behind GMT. Previously, local mean solar time was used in different parts of Iceland, the almanak had been based on Reykjavik mean solar time which was 1 hour and 28 minutes behind GMT. Summertime when it was applied was always by putting the clock an hour forward during the summer months, which made the clock time equal to GMT. The following list shows when this summertime was in force. The time of the clock change is specified in GMT. year from to ---- ---- -- 1908-1916 no summertime 1917 20.Feb. 0:00 21.Oct. 1:00 1918 20.Feb. 0:00 16.Nov. 1:00 1919-1938 no summertime 1939 30.Apr. 0:00 29.Nov. 2:00 1940 25.Feb. 3:00 3.Nov. 2:00 1941 2.Mar. 2:00 2.Nov. 2:00 1942 8.Mar. 2:00 25.Oct. 2:00 1943-1946 rule (first Sunday in March until first Sunday in winter) 1943 7.Mar. 2:00 24.Oct. 2:00 1944 5.Mar. 2:00 22.Oct. 2:00 1945 4.Mar. 2:00 28.Oct. 2:00 1946 3.Mar. 2:00 27.Oct. 2:00 1947-1967 rule (first Sunday in April until first Sunday in winter) 1947 6.Apr. 2:00 26.Oct. 2:00 1948 4.Apr. 2:00 24.Oct. 2:00 1949 3.Apr. 2:00 ******* 30.Oct. 2:00 (delayed by 1 week) 1950 2.Apr. 2:00 22.Oct. 2:00 1951 1.Apr. 2:00 28.Oct. 2:00 1952 6.Apr. 2:00 26.Oct. 2:00 1953 5.Apr. 2:00 25.Oct. 2:00 1954 4.Apr. 2:00 24.Oct. 2:00 1955 3.Apr. 2:00 23.Oct. 2:00 1956 1.Apr. 2:00 28.Oct. 2:00 1957 7.Apr. 2:00 27.Oct. 2:00 1958 6.Apr. 2:00 26.Oct. 2:00 1959 5.Apr. 2:00 25.Oct. 2:00 1960 3.Apr. 2:00 23.Oct. 2:00 1961 2.Apr. 2:00 22.Oct. 2:00 1962 1.Apr. 2:00 28.Oct. 2:00 1963 7.Apr. 2:00 27.Oct. 2:00 1964 5.Apr. 2:00 25.Oct. 2:00 1965 4.Apr. 2:00 24.Oct. 2:00 1966 3.Apr. 2:00 23.Oct. 2:00 1967 2.Apr. 2:00 29.Oct. 2:00 1968 7.Apr. 2:00 (actually GMT after this) "first day of winter" referred to above, means the first day of the 26 weeks of winter, according to the old icelandic calendar that dates back to the time the norsemen first settled Iceland. The first day of winter is always Saturday, but is not dependent on the Julian or Gregorian calendars. This is the reason for the discrepancy with October 1961. I can find out more exactly how to determine when it falls, if necessary. It is a pity I don't have that information handy, otherwise I could include it here. There are more serious discrepancies before 1941 which are not obviously explainable. What to do... (?) -- Adam David <adam(a)veda.is>

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Re: Timezone rule change in Europe [forwarded from Dik Winter]
by Dik.Winter＠cwi.nl 03 Dec '93

03 Dec '93

> Has anyone got precise details of the dates? i.e last sunday in october, or > last sunday after 23rd October (like uk) The paper was a bit unclear about that; the text was conflicting. On the one hand it talked about the current UK rule, on the other hand it talked about the last sunday in October. But I presume the rule now valid in the UK will be adopted by the remainder of the EU. So that would be first sunday after 23rd October. I will report about it when I know more. dik

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Re: Timezone rule change in Europe [forwarded from Dik Winter]
by Glenn.Wright＠UK.Sun.COM 03 Dec '93

03 Dec '93

Has anyone got precise details of the dates? i.e last sunday in october, or last sunday after 23rd October (like uk) Glenn. > > The ministers of transport of the European Union (formerly European > Community) have decided that by 1997 change from summer time to > winter time will be made by the end of october instead of the end > of september. This will bring the remainder of the EU in line with > the current rule in the United Kingdom and Ireland. It is to be expected > that other European countries will follow. [This according of my > paper of todaty, December 1.] > > (The European Union consists of: Netherlands, Belgium, Luxembourg, > France, Germany, Italy, United Kingdom, Ireland, Danmark, Spain, > Portugal and Greece.)

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Timezone rule change in Europe [forwarded from Dik Winter]
by ado 02 Dec '93

02 Dec '93

> From daemon(a)ncifcrf.gov Thu Dec 2 13:51:20 1993 > Return-Path: <daemon(a)ncifcrf.gov> > Received: from fcs280s.ncifcrf.gov by elsie (4.1/SMI-4.1) > id AA12625; Thu, 2 Dec 93 13:51:19 EST > Received: by fcs280s.ncifcrf.gov (4.1/NCIFCRF-3.0/AWF-2.0) > id AA04025; Thu, 2 Dec 93 13:43:34 GMT > Received: from charon.cwi.nl by fcs280s.ncifcrf.gov (4.1/NCIFCRF-3.0/AWF-2.0) > id AA04003; Thu, 2 Dec 93 13:43:28 GMT > Received: from boring.cwi.nl by charon.cwi.nl with SMTP > id AA02005 (5.65b/3.12/CWI-Amsterdam); Wed, 1 Dec 1993 22:07:42 +0100 > Received: by boring.cwi.nl > id AA12403 (4.1/2.10/CWI-Amsterdam); Wed, 1 Dec 93 22:07:42 +0100 > Date: Wed, 1 Dec 93 22:07:42 +0100 > From: Dik.Winter(a)cwi.nl > Message-Id: <9312012107.AA12403.dik(a)boring.cwi.nl> > To: ado(a)ncifcrf.gov > Subject: Timezone rule change in Europe > Status: RO > > The ministers of transport of the European Union (formerly European > Community) have decided that by 1997 change from summer time to > winter time will be made by the end of october instead of the end > of september. This will bring the remainder of the EU in line with > the current rule in the United Kingdom and Ireland. It is to be expected > that other European countries will follow. [This according of my > paper of todaty, December 1.] > > (The European Union consists of: Netherlands, Belgium, Luxembourg, > France, Germany, Italy, United Kingdom, Ireland, Danmark, Spain, > Portugal and Greece.) > > dik > -- > dik t. winter, cwi, kruislaan 413, 1098 sj amsterdam, nederland > home: bovenover 215, 1025 jn amsterdam, nederland; e-mail: dik(a)cwi.nl

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