Reasons for Decisions
This page documents reasons why the CLDR Technical Committee has made certain decisions. It provides a reference that can be cited, for example, when old issues resurface.
Before CLDR 1.9 / ICU 4.6, IE was listed (in supplementalData.xml) as using Sunday for the first day of the week.
As originally filed, #993 requested a change to Monday stating that it was more common. However the CLDR TC did not find that there was enough evidence for making a change. Also, Séamus Ó Ciardhuáin of NSAI, in a ticket comment, mentioned that although Monday is sometimes used as the firstDay in a workweek context, there are good reasons in history and law for using Sunday; in the latter case, a 1937 law defined Sunday as the firstDay, and an NSAI discussion reconfirmed this in 2004.
#2052 claimed that calendars in Ireland use Monday as firstDay, and that glibc follows this convention. CLDR checked some Irish transportation schedules; in 5 of 6, the firstDay was Monday. No changes were made under this ticket; they were subsumed by the changes discussed in the next bullet.
Per #2785 in CLDR 1.9, the behavior of Java (en_IE) and Windows/.NET were checked. Both of these used Monday, so IE was removed from the list of countries that used Sunday (thus defaulting to Monday, the default firstDay for 001 = the world).
Per #3500 in CLDR 2.0 there was a more comprehensive investigation of firstDay behavior across locales, comparing to Java and Windows. This confirmed Monday as firstDay for Ireland, and it was explicitly added to the Monday list.
However there is new recent feedback, including feedback from NSAI that firstDay should be restored to Sunday. Also, some of the transportation schedules checked under #2052 above as using Monday have changed to use Sunday, and Michael Everson has found several others that also use Sunday: Irish Rail, Aer Lingus, etc.
NSAI intends to lobby to have glibc, Windows, and Java use Sunday as the firstDay for Ireland.
Per CLDR discussion 2011-02-22, we will change firstDay back to Sunday for IE