An alternate calendar system briefly used by republican France. It had 360 days per year with 5 or 6 “intercalary” or leap days between years. It had 12 months of 30 days, which were comprised by 3 weeks of 10 days. Every day of the year had a unique name: a common plant, animal, mineral, or tool/equipment (ie January 31 was “Broccoli” and May 4 was “Silkworm”).
YSK because it’s an interesting alternative to the Gregorian calendar and the occasionally-proposed 13 month calendar.
Though it did have some problems such as starting in late September (very unusual for a calendar) and not having a robust leap-year system.
Starting a new year in the dead middle of Winter doesn’t make sense to me. Spring is when trees and flowers start blooming, hence the choice of March for the first month by Antique civilizations (also the start of their military campaigns which, although convenient, is not something I get behind really)