I wonder if this might have any bearing on the timing in ancient times:
QuoteBetween the Rural and City Dionysia, other two lesser festivals took place in honour of Dionysus: The Lenaia and the Anthesteria. The first took place in Athens in Gameliōn, roughly corresponding to January, while the latter was held each year from the 11th to the 13th of the month of Anthesteriōn, which was named after the festival.
The Lenaia was mostly an agrarian festival, believed to have included a procession, chanting, sacrifices, nocturnal rites and, possibly, special rituals for women. Beginning in the second half of the 5th century BCE, plays were performed, as in the City Dionysia, and awards were given, initially only for comedies, and later also for tragedies.
The Anthesteria were held for three days; the first one was called Pithoigia ("Jar Opening"), where libations were offered to Dionysus from the newly opened casks; the second one, called Choes ("Wine Jugs"), included wine-drinking contests while on the third day –Chytroi ("Pots")– pots of seed or bran were offered to honour the dead.
https://www.greeknewsagenda.gr/topics/culture…attic-festivals