The Syncretisms of Antinous are days to observe specific syncretism of Antinous to various other gods. Some of the syncretisms fall on their own days, but some also fall on the same days as other festivals or observances. In those cases, the syncretism is often observed alongside of, and sometimes as part of those other festivals.
In addition to these calendar dates, P. Sufenas Virius Lupus has descriptions of the many syncretisms of Antinous and association with other gods on a page housed at the Aedicula Antinoi blog. You can also purchase PSVL’s excellent book on the topic.
Monthly
Any New Moon – Men and Antinous
Any Full Moon- Endymion and Antinous
January
1 – Askelpios and Antinous
8 – Pan and Antinous
21 – Ganymede and Antinous
23 – Agathos Daimon and Antinous
27 – Dioskouri and Antinous
March
11 – Echmoun and Antinous
25 – Attis and Antinous
April
25 -Apis and Antinous
May
1 – Androklos and Antinous
15 – Hermes and Antinous
22 -Dioskouri and Antinous
Memorial Day -Achilleus and Antinous
June
21 – Appolon and Antinous
July
16 – Silvanus and Antinous
23 – Poseidon and Antinous
25 – Adonis and Antinous
25 – Aristaios and Antinous
31 – River Gods and Antinous
August
13 – Dioskouri and Antinous
13 – Vertumnus and Antinous
21 – Herakles and Antinous
22 – “Flower Heroes” and Antinous
September
19 – Eunostos and Antinous
21 – Iakkhos and Antinous
October
24 – Osiris and Antinous
December
21 -Dionysos and Antinous