Why February?

Some calendar-related history. The Roman calendar only had 10 months, because, curiously, the Romans didn’t demarcate (to determine or mark off the boundaries) winter. (I sure wish we could do the same)

In the 700s BCE, the second king of Rome, Numa Pompilius, changed it adding January and February to the ends of the calendar in order to conform to how long it actually took the Earth to go around the sun. The two new months were both originally 28 days long. 

In those day for a Roman March 1 (May Day) became New Year’s Day. Later in 153 BCE the beginning of the year was moved to January 1.

The root of the name doesn't come from the Roman god Februus. Even though that is very easy to assume. It come from the Latin word februa that means "to cleanse". The word februa comes from the Sabine word fēbrŭum, which means "a purgation" or "means of purification". Ovid connected februare to an Etruscan word for "purging". Also the Roman Festival called Februss that focused on purification and cleansing was filled with rituals to placate angry ghosts and send them away. It was the time of year for the ritual washing. The festival was also known as Februtus. It also gave its name to Juno Februalis, Februlis, or Februata, who was the patron deity of the month. It also gave its name to a supposed purification deity called Februus.