In the most recent episode of It’s Okay To Be Smart, host Joe Hanson explains why the month of February only has 28 days (and sometimes 29) through a somewhat confusing history of the Roman calendar which utilized a bit of superstition, a lot of politics, and a just a touch of astronomy.
Caesar came to power, things had gotten pretty confusing. Caesar had spent a lot of time in Egypt, where 365-day calendars were all the rage, so in 46 BC, he flushed Rome’s lunar calendar down the aqueduct and installed a solar calendar. January and February had already been moved to the beginning of the year, and Caesar added 10 days to different months to get a total of 365. And since a tropical year is a tad longer than 365 days, Julius added a leap day every four years, except they inserted it after February 23, right in the middle of the month. Apparently February is the trash heap of the calendar, just do whatever feels good. For all their work to reform the calendar and other stuff they did, the 7th and 8th months of the year were renamed for Julius and his successor Augustus Caesar, despite the fact that Pope Gregory would have to adjust it again in 1500 years.