Well, here is something I always use, and always forget how it’s done.
Even though googling helps it, sometimes the fastest way is to check where you know it is, your own blog! So here it is…
By default, the Gnome calender shows the 1st day of the week as Sunday. It can be easily changed.
First, to see your local settings :
Let’s say the output is en_US, then let’s back it up :
$ sudo cp /usr/share/i18n/locales/en_US /usr/share/i18n/locales/en_US.bak
Then edit your en_US file and change the value of first_weekday to 2.
If you wish to make Tuesday your first weekday of the calender, set it to 3 and so on.
Now update your locale’s.
$ sudo locale-gen
Now we need to restart gnome’s panel cause the calendar is on it, it need to be refreshed.
$ killall gnome-panel