Etching entitled: January (Gennaro), A Kitchen by Antonio Tempesta from his series: The Twelve Months (plate 1), 1599. January is the first month of the year in the Julian and Gregorian calendars and one of seven months with the length of 31 days. The first day of the month is known as New Year's Day. January (in Latin, Ianuarius) is named after Janus, the god of the doorway. The name has its beginnings in Roman mythology, coming from the Latin word for door (ianua) since January is the door to the year. January and February were the last two months to be added to the Roman calendar, since the Romans originally considered winter a month-less period.