Months of the year

January 31 days from Roman republican calendar month Januarius, named for Janus, god of doorways and beginnings

February 28 days usually, 29 in leap year from Roman republican calendar month Februarius, named for Februalia, the festival of purification held on the 15th to honour Februa, or Juno in her guise as the goddess of erotic love

March 31 days from Roman republican calendar month Martius, named for the god Mars

April 30 days from Roman republican calendar month Aprilis. The Romans considered the month sacred to the goddess Venus, and its name may derive from that of her Greek equivalent, Aphrodite. Another etymology connects the name April with the Latin aperire, "to open," in reference to the unfolding of buds and blossoms at this season, spring in the Northern Hemisphere.

May 31 days from Roman republican calendar month Maius, probably named for the goddess Maia

June 30 days from Roman republican calendar month Junius, probably named for the goddess Juno

July 31 days from Roman republican calendar month Julius (formerly Quintilis), named for Julius Caesar in 44 BC

August 31 days from Roman republican calendar month Augustus (formerly Sextilis), named for the emperor Augustus in 8 BC

September 30 days seventh month of early Roman republican calendar, from Latin septem, "seven"

October 31 days eighth month of early Roman republican calendar, from Latin octo, "eight"

November 30 days ninth month of early Roman republican calendar, from Latin novem, "nine"

December 31 days tenth month of early Roman republican calendar, from Latin decem, "ten"