January is the first month of the year, has 31 days, and is named after the two-faced Roman god Janus. January is the first month of the year in our modern day Gregorian calendar, and its predecessor the Julian calendar. It consists of 31 days and the first day of the month is known as New Year's Day.

Julius Caesar thought it would be appropriate for January, Janus' namesake month, to be the doorway to a new year, and when he created the Julian calendar, he made January 1 the first day of the year (this also put the calendar year in line with the consular year, as new consuls also took office that day).