How come February has only 28 days?

How come February has only 28 days?
February 27, 1987
Dear Cecil:

How come February only has 28 days (plus an extra day in leap year) when all the rest of the months have 30 or 31? Did they figure winter would go faster if the months were short?

— Randy Sue C., USA Weekend, Arlington, Virginia

Dear Randy Sue:

You may be closer to the truth than you think, scoop. But let's dispose of the other explanations first. A widely believed--but possibly erroneous--story has it that February is so short because the Romans borrowed a day from it to add to August. August was originally a 30-day month called Sextilis, but it was renamed to honor the emperor Augustus Caesar, just as July had earlier been renamed to honor Julius Caesar. Naturally, it wouldn't do to have Gus's month be shorter than Julius's, hence the switch.

But some historians say this is bunk. They say February has always had 28 days, going back to the 8th century BC, when a Roman king by the name of Numa Pompilius established the basic Roman calendar. Before Numa was on the job the calendar covered only ten months, March through December. December, as you may know, roughly translates from Latin as "tenth." July was originally called Quintilis, "fifth," Sextilis was sixth, September was seventh, and so on.

To meticulous persons such as ourselves, Randy, having the calendar run out in December and not pick up again until March probably seems like a pretty casual approach to timekeeping. However, we must realize that 3,000 years ago, not a helluva lot happened between December and March. The Romans at the time were an agricultural people, and the main purpose of the calendar was to govern the cycle of planting and harvesting.

Numa, however, was a real go-getter-type guy, and when he got to be in charge of things, he decided it was going to look pretty stupid if the Romans gave the world a calendar that somehow overlooked one-sixth of the year. So he decided that a year would have 355 days--still a bit off the mark, admittedly, but definitely a step in the right direction. Three hundred fifty five days was the approximate length of 12 lunar cycles, with lots of leap days thrown in to keep the calendar lined up with the seasons. Numa also added two new months, January and February, to the end of the year. Since the Romans thought even numbers were unlucky, he made seven of the months 29 days long, and four months 31 days long.

But Numa needed one short, even-numbered month to make the number of days work out to 355. February got elected. It was the last month of the year (January didn't become the first month until centuries later), it was in the middle of winter, and presumably, if there had to be an unlucky month, better to make it a short one.

Many years later, Julius Caesar reorganized the calendar yet again, giving it 365 days. Some say he made February 29 days long, 30 in leap year, and that Augustus Caesar later pilfered a day; others say Julius just kept it at 28. None of this changes the underlying truth: February is so short mainly because it was the month nobody liked much--a judgment with which I heartily concur. Frankly, if the Romans had cut it down to 15 minutes, it wouldn't have bothered me a bit.

— Cecil Adams

http://www.straightdope.com/columns/read/442/how-come-february-has-only-28-days