Volturnus is an ancient God and had his own flamen. Little is known about Him. He was reputed to be the father of Juturna, the fountain deity. It is possible that He is a God of the southeast wind, particularly damaging winds, or a river God. His sacred festival fell on August 27, though there is no information about what happened on that day.
These days are sacred to Him:
August 27 - Volturnalia