Quepennura Leap Week Calendar

In the First Place, Do You Know What the Present Worldwide Calendar is Like ?

The present worldwide calendar, formally called "Gregorian Calendar" as the calendar named after Pope Gregory XIII (Catholic Church), has the 400-year cycle.

The calendar has two kinds of years: 365-day common year and 366-day leap year.

Each leap year occurs in the year divisible by 4 but it does NOT exceptionally occur in the year divisible by 100 without in the year divisible by 400, so the calendar has 97 leap years in its cycle.

Therefore, the averaged year length of Gregorian Calendar is 365.2425 days: (365 days × 303 years + 366 days × 97 years) / 400 years = 365.2425 days.

Gregorian Calendar Has been Already OLD.

Gregorian Calendar has been already OLD. This is because the Gregorian-calendar averaged year length, 365.2425 days, does NOT match the present solar year, approximately 365.242189 days, which is the time that the same season takes to come again.

This means that one-day difference between the real season and the calendar will occur in approximately 3,216 years: 1 day / (365.2425 days - 365.242189 days) = 3,215.434... years.

Moreover, the solar year is getting SHORTER and SHORTER, so the one-day difference will occur earlier than 3,215 years and Gregorian Calendar will be USELESS in the future.

The Day of the Week for Each Date Changes Every Year.

As mentioned above, one common year of Gregorian Calendar has 365 days and one leap year has 366 days. However, each of these cannot be divided by 7, the number of the days of the week (364 is the nearest number to 365 or 366 in those divisible by 7).

This means that the day of the week for each date on Gregorian Calendar changes every year and it confuses us. We must wait for 400 years for the same date to be the same day of the week because the 400-year cycle has exactly 20,871 weeks.

Some people believe in Friday the 13th is a bad day. At least for them, it seems to be one kind of hell that Friday the 13th comes once or more times every year. Of course, this is caused because the day of the week for each date changes every year.