personal worldbuilding notes, calendar/date format shenanigans inspired by a straight up shitpost
Northern Isarthakan calendar (most of Krasma and umAŕneth, Faekak, Tovelen and Ïslekhante in north-central Dorzhen, also used worldwide):
322 or 321 days long divided into 6 seasons consisting of 3 months* (17 to 18 days) each, with the spring and fall equinoxes as their own separate days, with the leap day in mid-winter
typical date formats: yyyy/s/m/dd (worldwide), yyyy/mm/dd (Kǁingarúp-Egyashko-K'epeħa), dd/m/s/yyyy (umVarlakh-thalKanneqith)
Southern Isarthakan calendar (most of Dorzhen, Øttivileq {western umAŕneth), the Ciskrasmic Isles, Auakea, Uyatkuch and Dhaalettu in south-central Krasma):
same year length, but subdivided into 14 months* of 23 days each with one clipped off of the first month in short years.
typical date formats: yyyy/mm/dd (most areas), dd/mm/yyyy (Øttivileq and the Ciskrasmic Isles), mm/yyyy/dd (Auakea, where even the people who live there have no idea why they don't just use a more sensible system)
* Isarthaka doesn't actually have any satellites beyond the occasional temporary asteroid caught in orbit around the planet; these periods are completely arbitrary as a result.