Even if `ncal: setlocale: No such file or directory` is about my system not having "en_US" generated and falling back to LANG=C, I just can't find a place showing week 1 of 2019 being 6th-12th January 2019 for US.
f.ex: https://www.timeanddate.com/calendar/custom.html?year=2019&country=1&wno=1&holm=1&df=1 https://savvytime.com/week-number/united-states/2019 https://www.epochconverter.com/weeks/2019
