Origin of the names of the months
Only a few names of the month were derived from Roman deities. Most simply came from the numbers of the months or -- in two cases -- in honor of Roman emperors.
Called Aprilis, from aperire, "to open". Possible because it is the month in which the buds begin to open.
The fourth month was named in honor of Juno. However, the name might also come from iuniores (young men; juniors) as opposed to maiores (grown men; majors) for May, the two months being dedicated to young and old men.
It was the month in which Julius Caesar was born, and named Julius in his honor in 44 BCE, the year of his assassination. Also called Quintilis (fifth month).
Originally this month was called Sextilis (from sextus, "six"), but the name was later changed in honor of the first of the Roman emperors, Augustus (because several fortunate events of his life occurred during this month).
The name comes from septem, "seven".
The name comes from octo, "eight"
The name comes from novem, "nine".
The name comes from decem, "ten".