Don't be surprised and think you're a time traveler while in Ethiopia. Ethiopia does have its own calendar and each year has 13 months.
According to The Culture Trip, Ethiopians call the method used to calculate the calendar the Bahere Hasab, or 'sea of thoughts'. The calendar system begins with the idea that Adam and Eve lived in the Garden of Eden for seven years before they were expelled for their sins. After they repented, the Bible says that God promised to save them after 5,500 years.
The Ethiopian and Gregorian calendars both use Jesus' date of birth as a starting point for their calculations. There is a difference between the two calendars due to the alternative calculations used in determining this date. The Ethiopian Orthodox Church believes Jesus Christ was born in 7 BC, 5,500 years after God's promise to Adam and Eve.
Number of days in Ethiopian calendar
The Ethiopian calendar has 13 months of the year, 12 of which have 30 days. The last month, called Pagume, had five days, and six days in a leap year. The four-year leap cycle of the Ethiopian Calendar is associated with the four evangelists of the Bible. The first year after the Ethiopian leap year was named the year of John, and was followed by the year of Matthew and then the year of Mark. Years with a 6th epagomenal day are traditionally designated as Luke's years.
13th month name in Ethiopia
Pagume is a name that appears in the 13th month of the Ethiopian calendar. Pagume comes from the Greek word epagomene, which means 'forgotten days when a year is counted'. This month has five days or six days in a leap year.
According to the Ethiopian calendar, a year has 365 days, six hours, two minutes and 24 seconds. Every four years, the six hours increase to 24 hours and become the sixth day of a leap year. Once in 600 years, two minutes and 24 seconds add up to a full day and form the seventh day, which the Ethiopians call rena mealt and rena lelit.
Every 600 years, a unique star named Aqede appears and overshadows the Sun, causing a total solar eclipse. As narrated by ancient Ethiopian books, the Ethiopian elite knew before modern scientists about a solar eclipse and could predict when it would occur with accuracy.
Ethiopian calendar today
Modern Ethiopia still adheres to the ancient calendar. Most Ethiopians are familiar with the Gregorian calendar and but some use the two calendars interchangeably.
As one of the few countries in the world with its own calendar system, Ethiopia celebrates important holidays on different days from the rest of the world. For example, Ethiopia celebrates the new year on September 11, not on January 1.