[tz] Irish Standard Time vs Irish Summer Time

Stephen Colebourne scolebourne at joda.org
Sun Dec 10 08:45:25 UTC 2017

This whole thread appears to have missed the fact that Ireland is in
the EU, and thus the normal EU rules on time apply.


"Standard Time
In parallel to the summertime arrangement in the European Union, the
Member States apply three different time zones or standard times. The
decision on the standard time is a national competence. The standard
time is determined in relation to GMT (Greenwich Mean Time)."
"Three Member States (Ireland, Portugal and United Kingdom) apply GMT"

As such, this thread is essentially choosing between two ways of
expressing the same thing - the EU way and the way it is expressed in
Irish law.
The EU define "standard" one way. Irish law defines it the other way.

Since EU law takes precedence over national laws, I'd suggest the EU
definition should be used, ie. tzdb should not change.


AFAIK, these are all defined in terms of "standard"

On 8 December 2017 at 06:38, Paul Eggert <eggert at cs.ucla.edu> wrote:
> On 12/05/2017 02:16 AM, Derick Rethans wrote:
>> No, I meant "Irish Standard Time". Ireland is "odd" because their
>> standard time is what the rest of the British Isles calls "Summer Time"
>> (BST). So Ireland uses "Irish Standard Time" and "GMT".
> Thanks for pointing this out; I was unaware that Ireland observes negative
> daylight-saving time in winter, instead of positive daylight-saving time in
> summer. This arguably is clearer than the common practice in North America
> and Europe, where "standard time" is observed only in a relatively small
> fraction of the year. I installed the attached proposed patch to fix the
> commentary along the lines that you suggested, and to change tm_isdst as
> well. UT offsets and abbreviations are unaffected by this change.

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