Why Does February Have 28 Days?

Thirty days hath September, April, June, and November; all the rest have thirty-one ... except for February, for some reason. How did this poor month become the runt of the calendar, anyway? Blame the Romans and their weird superstitions.

Do You Calen-dare?

Way back in the early days of ancient Rome, months weren't really a thing. Anybody paying attention could feel when the seasons changed and see when the sun came up in the morning and went back down at the end of the day. Legend has it that the maybe-mythical founder of Rome, Romulus, decided there was a need for a calendar. Citing the growing number of festivals and activities throughout the year, he needed some sort of way to keep track of what was happening when. Thus, the 10-month Roman calendar was born. This lunar calendar began in March with the spring equinox and ended in December. The days left out? Well, that harvest-less chunk of time was pretty useless anyway.

29 Days Has Ianuarius

Rome's second king, Numa Pompilius (753–673 BC), revised this calendar a bit further. He wanted to make it more accurate by syncing it up with a year's 12 lunar cycles, which is about 355 days long. With so many extra days on his hands, he cooked up the idea of January and February. The thing is, Numa was a superstitious dude, and in those days, even numbers were considered unlucky. Instead of settling on each month having 28 days each, he mixed up the number of days in each month so they were all odd. But he had to have one exception to make it work: our friend February. Here's what he was working with at this point:

Martius: 31 days

Aprilius: 29 days

Maius: 31 days

Iunius: 29 days

Quintilis: 31 days

Sextilis: 29 days

September: 29 days

October: 31 days

November: 29 days

December: 29 days

Ianuarius: 29 days

Februarius: 28 days

Extreme Calendar Makeover: Roman Edition

After a few years on this schedule, the season started to fall out of sync (it only accounted for 355 days, after all). Romans threw in an entire leap month every once in a while — Mercedonius — to sync it back up. To make matters even more confusing, sometimes politicians would decide to throw in extra leap months, or nix leap months, to prolong their time or cut another's time in office. It was a mess. By the time Julius Caesar came into power in 49 BC, he was fed up with this confusing garbage. Time for another calendar makeover!

Caesar killed the leap month in favor of moving to a sun-based calendar, like the Egyptians had, instead of a moon-based one. (To get things back on track, the year 46 BCE was 445 days long.) He added in extra days to the calendar year so that the year averaged out to 365.25 days, very close to the actual average length of a year: approximately 365.2425 days. The leap month became a leap day that was tacked on to February every few years, and the calendar was finally a sensible schedule. Oh, until Pope Gregory shuffled it around again, but that's a tale for another month.

Why Does February Only Have 28 Days?

Written by Joanie Faletto February 21, 2018

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