In fact, we used to have 13 months in a calendar year. So why is our calendar 12 months instead? And why did it change? According to the NCESC, there's a long history behind this alteration.

The 2025 summer solstice takes place Friday, June 20, at 10:42 p.m. ET. The summer solstice is the longest day of the year, ...

"When Numa Pompilius took reign [of Rome], he decided to make the calendar more accurate by lining it up with the year’s 12 lunar cycles," according to the Children's Museum of Indianapolis.

"When Numa Pompilius took reign [of Rome], he decided to make the calendar more accurate by lining it up with the year’s 12 lunar cycles," according to the Children's Museum of Indianapolis.

The meteorological start date is based on our 12-month civil calendar and the annual temperature cycle.” While these are the technical start dates for each season, depending on where you live ...

Languages: English, French Ramadan is the ninth month of the 12-month Islamic lunar calendar. Since the calendar is based on the moon's cycles, Ramadan's start date shifts earlier each year and ...