emacs org-mode language of time stamps

Question

Depending on the computer I use, abbreviation for day names changes: it would be mon, tues, wed… on an american ubuntu and lun., mar., mer.… on a french ubuntu etc.

This is causing problem with the org-habit module of org-mode which stop working correctly when those format are mixed.

This localization is present even when I bypass my emacs configuration file using the -Q option.

How can I sort this out?

Answer 1

;; System locale to use for formatting time values.
(setq system-time-locale "C")         ; Make sure that the weekdays in the
                                      ; time stamps of your Org mode files and
                                      ; in the agenda appear in English.