Only a few names of the month were derived from Roman deities. Most simply came from the numbers of the months, or, as in two cases, in honor of Roman emperors.

January -31 days
Named after the Roman god of beginnings and endings Janus (the month Januarius)

February – 28/29 days
The name comes either from the old-Italian god Februus or else from februa, signifying the festivals of purification celebrated in Rome during this month.

March – 31 days
This is the first month of the Roman year. It is named after the Roman god of war, Mars.