January is named for Janus, the Roman god of doors and gates.
January and February were put on the calendar after all the other months. This is because in the original Roman calendar, winter did not have months. Although March was originally the first month, January became the new first month because that was when people chose the new consuls (Roman leaders). The month has 31 days.
January is a winter month in the Northern Hemisphere and a summer month in the Southern Hemisphere. In each hemisphere, it is the seasonal equivalent of July in the other. Perihelion, the point in its orbit where the Earth is closest to the Sun, also occurs in this month, between January 2 and January 5. January begins on the same day of the week as October in common years and on the same day of the week as April and July in leap years. January ends on the same day of the week as February and October in common years and on the same day of the week as July in leap years. January is the only month of the year that always has a "twin" - a month that both begins and ends on the same day of the week as it does. In a common year, this is October, and in a leap year, July.
Every year, January both starts and finishes on the same day of the week as May of the previous year, as each other's first and last days are exactly 35 weeks (245 days) apart.
In common years immediately before other common years, January starts on the same day of the week as April and July of the following year, and in leap years and years immediately before that, September and December of the following year. In common years immediately before other common years, January finishes on the same day of the week as July of the following year, and in leap years and years immediately before that, April and December of the following year.
January's flower is the carnation with its birthstone being the garnet. The meaning of the garnet is constancy.
The first day of January is called New Year's Day. It is said that it became this date when Roman consuls took office on this day in
153 BC. Different calendars across Europe made this the start of the New Year at different times, as some observed it on March 25.
Reaching over from December, the Christmas season in Christianity also extends into this month. Eastern churches celebrate Christmas on January 6 or January 7, and Epiphany on January 18 or January 19 - In Western Christianity this occurs on January 6, with Christmas occurring on December 25.
January 1 is celebrated the Solemnity of Mary, the Mother of God, that is a feast day of precept of the Blessed Virgin Mary.