System-wide ISO time format

I am trying to set the system-wide date and time format to ISO 8601.

Setting the LC_TIME variable to en_DK.UTF-8 as suggested elsewhere does not seem to provide a conformant implementation. Furthermore, setting the TIME_STYLE variable to posix-long-iso does not seem to do anything at all.

Is there a locale that supports this format that I am not aware of, or any other method of approaching this ?

Thank you for your help !

There is the custom en_SE locale, which is en_US with the date format taken from sv_SE.

I’m patching it into glibcLocales, take a look: nix-config/modules/locale.nix at 059f74a5a49d7f47d3b484d233cdf191becf4055 - fugi/nix-config -

(I don’t know if there’s a better way to do it, but it works.)