Why February has only 28 days?
The ancient Romans were pretty pragmatic. They didn't see a need to put a label on days that didn't need a label. Their calendar began on the first day of March and ran through the end of December. It was a ten month calendar (decem means ten) of 304 days. A calendar was needed to mark schedulable events. Wars could only be fought during acceptable weather, crops could only be planted or harvested during acceptable weather, festivals weren't much fun in bad weather. The period between the last day of December and the first day of March was dreary. Nothing much happened, so there wasn't a need to give it names on the calendar.