Why don't we have a 13 month year?

It is based on the calender of the Roman Empire.

The Calender was originally ten (lunar) months long beginning March ( the vernal equinox) and ending in December ( December means 10th month) with the time between the end of december and the next equinox being 'outside the calender. The Calender existed to regulate religious festivitys, and define the lengh of political offices, the romans had no 'weeks' .

The calender was reformed into 12 months ( precise date unknown the Romans believed approximately 713BC) and two months where added to the end of the year, ( January and February) Eventually March ceased to be new year in 153BC when political changes meant that the two chief roman magistrates ( the Consuls) began to be elected on February the 1st.

The Calender spread with the Roman Empire and being integral to the liturgical year of the Catholic and Orthodox Christian faith spread with those religions as well.

Ethiopia was heart of the Kingdom of Axum in Roman times and was NOT part of the Roman Empire, There christianity came from being directly evangelised by Early christian missionarys and so is not an offshoot of Catholic or Orthodox church. This means they put the christian festivals on there own calender rather than adopting the one of the Roman empire.

13 Months In A Year

Guess it must be because in the world we live in, 13 is a bad number. There were orgininally 13 apostles. A lunar month = 28 days x 13 = 364. That means we'd lose a day every 12 months. Which would make a leap year = 368 days. Difficult to deal with. Better stick with the system we've got.

By the way, there is no such month as Octember. Someone passed me a cheque many years ago dated, Octember 32nd 1973. So read the small print.

It is because the lunar calendar does not accurately represent the actual time taken for the Earth to revolve around the sun once, which is 365.25 days. You could argue that the "12 month" part is utterly arbitrary.

The lunar cycle is 29.53 days, and thus there are 354.36 days to twelve lunar "months". You can see how this wouldn't accurately reflect an actual solar year, which is really more important as far as seasons etc go.

The only "real" lunar calendar is the one Islam uses, which is totally out of whack with solar years.

In the end, I would say that we use the Gregorian calendar because it is more convenient and because of the ongoing, or in some cases, renewed cultural influence of Rome on Western civilization.

Julius Caesar's astronomers explained the need for 12 months in a year and the addition of a leap year to synchronize with the seasons. At the time, there were only ten months in the calendar while there are just over 12 lunar cycles in a year.

The months of January and February were added to the calendar and the original fifth and sixth months were renamed July and August in honour of Julius Caesar and his successor Augustus.

These months were both given 31 days to reflect their importance, having been named after Roman leaders.

Julius Caesar's astronomers explained the need for 12 months in a year and the addition of a leap year to synchronize with the seasons. At the time, there were only ten months in the calendar while there are just over 12 lunar cycles in a year.

The months of January and February were added to the calendar and the original fifth and sixth months were renamed July and August in honour of Julius Caesar and his successor Augustus.

These months were both given 31 days to reflect their importance, having been named after Roman leaders.

It would be logical to have 13 equal length months, but it probably has to do with superstition... when the calendars we use today were established they probably didn't want a 13th month. Same reason as why some buildings don't have a 13th floor (seriously, check out the buttons on elevators...some tall buildings go from 12 to 14)

This Site Might Help You.

RE:

Why don't we have a 13 month year?

Such as a lunar calendar, like in Ethiopia.

It takes 29.53 days (29 days, 12 hours, 44 minutes) to complete one lunar cycle. 13 x 29.53 days = 383.89 days which is longer than a year.

12 x 29.53 days = 354.36 days which is shorter than a year.

If you used the lunar calendar the seasons wouldn't stay in the same months ie Christmas one year might be in winter and in a couple of years time it might be in summer.

Probably because no other countries have a 13 month year. It's already difficult enough having to change from feet to meters, and dollars to other money!