Official definition and origin of the term "Central European Time"
Is there an official definition of the term "Central European Time" (CET), specifically which UTC offset(s) it refers to? If there is no official definition, where did the term originate from? I asked the information desk at the EU (Europe Direct) to help me find links to relevant legislature, but their reply was that term CET is "not regulated at a EU level, but internationally". All credible sources I have found, say that CET is a constant UTC+1. The closest thing I have found to an authoritative document, is the German Time Act from 1978. It says: "Legal time is Central European Time. It is defined as Coordinated Universal Time plus one hour." There is no reference to the origin of this definition, and no information of whether anyone other than the Germans agree on this definition. http://www.cl.cam.ac.uk/~mgk25/time/zeitgesetz.en.html On the EU's web pages (for instance http://europa.eu/contact/index_en.htm) times are usually given in CET, not CEST (Central European Summer Time), even though daylight saving time is currently observed. Google gives a few hundred thousand results for CET on europa.eu, and numerous of these results are hits on dates in the daylight saving time period. I think it makes more sense to define CET as alternating between UTC+1 (standard time) and UTC+2 (when DST is observed). (See http://time.is/CET for a more elaborate definition.) This is in line with for instance the US time zones Pacific Time and Eastern Time, which refer to the time currently observed, whether it is standard time or daylight saving time. Even Scharning Time.is - exact time for any time zone http://time.is/
On 10/23/2015 01:52 PM, Even Scharning wrote:
All credible sources I have found, say that CET is a constant UTC+1.
Many sources also use "Central European Time" to denote either UTC+1 or UTC+2, depending on whether daylight saving time is in use. For example, "Most of the cities in this book are on Central European Time, which is 1hr. ahead of Greenwich Mean Time (GMT) and observes Daylight Saving Time during the summer." -- Let's Go Europe 2012. North American practice is to use phrases like "Pacific Time" when one wants the time zone independently of whether DST is in use, and phrases like "Pacific Standard Time" and "Pacific Daylight Time" when one wants to specify whether DST is in use. There's no similar convention for European time zones, so phrases like "Central European Time" are ambiguous in practice, and careful writers should specify which meaning is intended -- as is done in the abovementioned quote from "Let's Go Europe".
Hi Even, My understanding is that there is no specific European directive that requires that a country use a particular offset, year round. However, whatever the country uses, there *is* a directive that states precisely when summertime begins and ends: http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32000L0084:EN:NO... This is reflected in the EU rules that European entries then generally make use of in the database. As far as the timezone database is concerned, code does not reference the term "Central European Time". A short name such as "CE%sT" is not official anything but convenience, and is certainly not unique. Eliot On 10/23/15 8:52 PM, Even Scharning wrote:
Is there an official definition of the term "Central European Time" (CET), specifically which UTC offset(s) it refers to?
If there is no official definition, where did the term originate from?
I asked the information desk at the EU (Europe Direct) to help me find links to relevant legislature, but their reply was that term CET is "not regulated at a EU level, but internationally".
All credible sources I have found, say that CET is a constant UTC+1. The closest thing I have found to an authoritative document, is the German Time Act from 1978. It says: "Legal time is Central European Time. It is defined as Coordinated Universal Time plus one hour." There is no reference to the origin of this definition, and no information of whether anyone other than the Germans agree on this definition. http://www.cl.cam.ac.uk/~mgk25/time/zeitgesetz.en.html
On the EU's web pages (for instance http://europa.eu/contact/index_en.htm) times are usually given in CET, not CEST (Central European Summer Time), even though daylight saving time is currently observed. Google gives a few hundred thousand results for CET on europa.eu, and numerous of these results are hits on dates in the daylight saving time period.
I think it makes more sense to define CET as alternating between UTC+1 (standard time) and UTC+2 (when DST is observed). (See http://time.is/CET for a more elaborate definition.)
This is in line with for instance the US time zones Pacific Time and Eastern Time, which refer to the time currently observed, whether it is standard time or daylight saving time.
Even Scharning Time.is - exact time for any time zone http://time.is/
On Fri, 23 Oct 2015, Even Scharning wrote:
I think it makes more sense to define CET as alternating between UTC+1 (standard time) and UTC+2 (when DST is observed). (See http://time.is/CET for a more elaborate definition.)
In a similar fashion, people use GMT to mean both GMT and BST (British Summer Time, UTC+1) for Europe/London, notably, Google Calendar. The amount of confusion that causes is staggering, especially among my American co-workers scheduling meetings. I'd strongly suggest you use CET for UTC+1 and CEST for UTC+2 exclusively. cheers, Derick
Yes, to some people it comes as a shock that the time in London is not always GMT. :) But "Central European Time" is easily reworded into "the current time in Europe". "Greenwich Mean Time" does not translate into "British (Summer) Time" in the same way, at least not if you just look at the meaning of the words. Even Scharning Time.is - exact time for any time zone http://time.is/ ---- Facebook: https://www.facebook.com/exact.time.is Twitter: https://twitter.com/Time_is Google+: https://plus.google.com/+timeis/ On 2015-10-24 14:17, Derick Rethans wrote:
On Fri, 23 Oct 2015, Even Scharning wrote:
I think it makes more sense to define CET as alternating between UTC+1 (standard time) and UTC+2 (when DST is observed). (See http://time.is/CET for a more elaborate definition.)
In a similar fashion, people use GMT to mean both GMT and BST (British Summer Time, UTC+1) for Europe/London, notably, Google Calendar. The amount of confusion that causes is staggering, especially among my American co-workers scheduling meetings. I'd strongly suggest you use CET for UTC+1 and CEST for UTC+2 exclusively.
cheers, Derick
"Even" == Even Scharning <tzdb@time.is> writes:
Even> Yes, to some people it comes as a shock that the time in London is Even> not always GMT. :) Nor is the difference between America/Los_Angeles and Europe/London always 8 hours. It can be 7, 8, or 9, depending on the time of year. Scheduling international video skype calls is such a pain. :) -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 <merlyn@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/> Perl/Unix consulting, Technical writing, Comedy, etc. etc. Still trying to think of something clever for the fourth line of this .sig
Derick Rethans said:
In a similar fashion, people use GMT to mean both GMT and BST (British Summer Time, UTC+1) for Europe/London, notably, Google Calendar.
No, certain idiots (notably Microsoft and Google) do. No sane person does. -- Clive D.W. Feather | If you lie to the compiler, Email: clive@davros.org | it will get its revenge. Web: http://www.davros.org | - Henry Spencer Mobile: +44 7973 377646
participants (6)
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Clive D.W. Feather -
Derick Rethans -
Eliot Lear -
Even Scharning -
merlyn＠stonehenge.com -
Paul Eggert