As written by Jeff Law: This URL shows an official response to a question about locale dates within the EU. Basically they adopted ISO 8601. http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:C:2004:78E:0447:0447:EN:PDF ISO 8601: http://dotat.at/tmp/ISO_8601-2004_E.pdf 2.2.8 calendar week time interval of seven calendar days starting with a Monday
*** Bug 13946 has been marked as a duplicate of this bug. ***
*** Bug 13948 has been marked as a duplicate of this bug. ***
*** Bug 13197 has been marked as a duplicate of this bug. ***
The patch by Jeff Law (except pt_PT change) has been committed.