When is Week 1 of 2019 according to US week numbering?
Wikipedia says that January 1th is part of Week 1, but my ncal(1) seems to uses another week numbering system.
@pmakholm it looks like it works in both the us (weeks starting on sunday) and ISO. Fortunately, recently places in the us have moved to ISO standard week countings and left the week starting on Sunday.
Maybe one day the US will start its week on Monday
@jlamar That is the ISO-8601 week numbering that is used in most of Europe (when week numbers are used at all).
An equivalent rule is 'Week 1 contains the first Thursday of the year).