Why does February have 28 days?

It's the Romans' fault. Our modern calendar is loosely based on their old, confusing one. Though records on the Roman calendar are sparse and sketchy, legend has it that Romulus, the first king of Rome, devised a 10-month lunar calendar that began at the spring equinox in March and ended with December. It is unclear whether there were any official months between December and March, but it's likely they were left off because the wintertime wasn't important for the harvest.

The second king of Rome, Numa Pompilius, decided to make the calendar more accurate by syncing it up with the actual lunar year�which is about 354 days long. Numa tacked on two months�January and February�after December to account for the new days. The new months each had 28 days. But that didn't sit well with Numa because even numbers were considered bad luck at the time.

So, he added a day on to January, giving the year an odd-numbered 355 days. No one knows why February was left with 28 and remained an unlucky month.