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A leap cycle of 231 years contains 56 leap days or 41 leap weeks and thus overall 84371 days and 12053 weeks or 2772 twelfth-of-a-year months, spanning roughly 2857 lunations. Its mean year length is 365.(24) days or 365 days, 5 hours, 49 minutes and about 5.45 seconds. It is the cycle after which the Dee calendar and the Dee-Cecil calendar with their 33-year leap cycle repeat its days of the week count.

Leap rule[]

Unlike the 4-year or 28-year leap cycle of the Julian calendar and the 400-year leap cycle of the Gregorian calendars as well as the 900-year leap cycle of the Revised Julian calendar, this leap cycle is not using Olympiads with exceptions but usually delays one in eight leap days by one year, which creates a 33-year subcycle of which there are 7 in total, each starting with a different day of the week. There are different approaches possible to define when two leap days are five years apart instead of the usual four. Likewise, the distribution of leap weeks is a matter of convention, even if it follows a general rule as the one laid out in ISO 8601.

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