January
January is named after the Roman god Janus.
February
The ritual Februa held on February 15 full moon in the old roman calender
Mars
‘In ancient Rome several festivals of Mars took place in March, presumably in preparation for the campaigning season, since Mars was a god of war.’
June
Having conceded one month to a Greek deity, we’re now back with the Romans: June is named after the ancient Roman goddess Juno, wife of Jupiter and goddess of marriage and childbirth. June was also once sometimes known as midsummer month.
July
The first month in the calendar named after a real person, July was named in honour of Julius Caesar after his death in 44 BC, July being the month of his birth.
October
More of the same: octo is the Latin for ‘eight’, for that ten month calendar. Two months were added to the end of the calendar year around 713 BC, and the beginning of the year was moved to 1 January in 153 BC.
November
The pattern continues: November comes from novem, ‘nine’. November is also, we’re afraid, used ‘with allusion to November’s position at the end of the year, and to the characteristic greyness, gloominess, etc., associated with it in the northern hemisphere’. The earliest known example of this allusive use comes from Jane Austen’s posthumously published novel Persuasion.
December
And we finish off the year with December, from decem, ‘ten’. The month also comes with a brace of adjectives: Decemberish and Decemberly, the latter of which can also be used as an adverb. And there you have it: a whole calendar year of etymologies to see you through the whole of 2016.