Hellenion’s Dec 2019 Festival calendar,
from https://www.hellenion.org/calendar/
Poseideon – Gamelion
Year 3 of the 699th Olympiad
7 Country Dionysia (?)
12 Full Moon
14 Libation to Dionysos
15 Poseidea
22 Heliogenna; Winter Solstice
23 Heliogenna; Haloa
26 Dark of the Moon
27 Hekate’s Deipnon
28 Noumenia
29 Agathos Daimon
31 New Year’s Eve