The Cresian calendar is a nonstandard system of timekeeping on Cresia. The official system of timekeeping is Derived Time (DT), required on all official documents. However, the Cresian calendar and Cresian Time (CT) is used for everyday life.
The tropical year of Cresia isdd, and its solar day dh. Thus, there are solar days in a tropical year, or about 9,650,515 days in 40,000 years. Any year that is divisible by 4, 50, or 125 is a leap year, unless it is also divisible by 800 but not 8000, which results in 10,515 leap years per 40,000 years.
The Cresian calendar has 10 months of 24 or 25 days and a ten-day week. The tradition of ten-day weeks carried over from the Old Cresian calendar. The leap day is added to the calendar as the 25th day of the tenth month.
An example of a month starting on C1: