[Animats]

Yes. Worst case is not printing the year, even for items which are from a previous year. ISO 8601 is the international standard on how to write dates and times. Get used to it. XKCD: https://xkcd.com/1179/

Japan has a strange tradition of dates and times such as 7-3 2530. Tokyo TV schedules have values like that. "2530" means 0130 on the next day. Businesses that close after midnight may give their closing time as "2600". This comes from a strange combination of military time plus a historical tradition that days start at dawn. At least it's unambiguous.

[tectec]

I really like this idea. In fact just yesterday I was thinking about it makes much more sense to group activities that happen after midnight with the "previous" day.