A commenter asked about the date of the Adonia. I confess I had never considered the matter, and posted the German text of the Realencyclopadie entry in the comments. Here is a translation.
Adonia. The feast of Adonis, celebrated in midsummer festival, whose main component is the lament for the death of Adonis who was represented by wooden dolls. The festival, of uncertain origin, is certainly an ancient one on the soil of Greece, Asia Minor and Syria, first mentioned at Athens under the name A)dwnia (Aristophanes Peace 419. Plutarch Nicias 13; Alcibiades 18) on the occasion of the Sicilian expedition as a private celebration for women. In the 4th century B.C., the comic writers several times refer to it as for courtesans. So in Diphilus, fragment 43, 39 (II 554 K., ibid. 557; in the Theseus of Diphilus, the courtesans gave each other obscene riddles at the Adonia).
An honorary decree of the Thiasotai of Aphrodite for their leaders from the year 302 (Dittenberger Syll. 427) sets out his services in the πομπή (solemn procession) of the Adonia, which must therefore have been a major festival.
There is a portrayal of a splendid celebration of the Adonia in Alexandria, favored by Ptolemy Philadelphus, in Theocritus, 15th Idyll; a description of the celebration in Byblos, probably from the 1st century A.D., in [Lucian] de dea Syria 6ff; in Antioch in 362 AD (Ammianus Marcellinus XXII 9, 15) the festival was still celebrated annually. For the history of the god and its importance see Adonis.
The opening of the 15th idyll of Theocritus, and a link to the full English version, is in the post referenced above. The hymn that is sung refers to Adonis receiving all the fruits — late summer, perhaps? — while another bit refers to “Oh dear, oh dear, Gorgo! my summer cloak’s torn right in two”, and the footnote suggests that it may have been held on the longest day.
Of course this is Ptolemaic Alexandria. We need not suppose the festival was held on the same day everywhere. Indeed in the Greek world, where each city could have different months, where the year started at different times, and there was no agreement on any universal chronology, it would be quite difficult to hold a festival on the same day throughout the Greek world, except by tying it to the solstice or some other astronomical event.
We’re used to the Christian chronology, which is universal. But that was a product of late antiquity, of the labours of Eusebius of Caesarea. It did not exist in the classical Greek period.
UPDATE: Aristophanes, Peace, is here:
HERMES: Is it then for this reason that these untrustworthy charioteers have for so long been defrauding us, one of them robbing us of daylight and the other nibbling away at the other’s disk?
TRYGAES: Yes, certainly. So therefore, Hermes, my friend, help us with your whole heart to find and deliver the captive and we will celebrate the great Panathenaea in your honour as well as all the festivals of the other gods; for Hermes shall be the Mysteries, the Dipolia, the Adonia; everywhere the towns, freed from their miseries, will sacrifice to Hermes the Liberator; you will be loaded with benefits of every kind, and to start with, I offer you this cup for libations as your first present.
Plutarch, Alcibiades, is here. The time is the arguments at Athens over sending the disastrous expedition to Syracuse.
After the people had adopted this motion and all things were made ready for the departure of the fleet, there were some unpropitious signs and portents, especially in connection with the festival, namely, the Adonia. 3 This fell at that time, and little images like dead folk carried forth to burial were in many places exposed to view by the women, who mimicked burial rites, beat their breasts, and sang dirges.
Plutarch, Nicias, here refers to the same events:
7. Not a few also were somewhat disconcerted by the character of the days in the midst of which they dispatched their armament. The women were celebrating at that time the festival of Adonis, and in many places throughout the city little images of the god were laid our for burial, and funeral rites were held about them, with wailing cries of women, so that those who cared anything for such matters were distressed, and feared lest that powerful armament, with all the splendour and vigour which were so manifest in it, should speedily wither away and come to naught.
These last two come from Lacus Curtius, the splendid site created by Bill Thayer. Here the Adonia is being celebrated at Athens when the expedition is despatched — but when was this, I wonder?
Bill has linked ‘adonia’ in the Alcibiades to a dictionary article that he has digitised, here.
ADOʹNIA (Ἀδώνια), a festival celebrated in honour of Aphrodite and Adonis in most of the Grecian cities, as well as in numerous places in the East. It lasted two days, and was celebrated by women exclusively. On the first day they brought into the streets statues of Adonis, which were laid out as corpses; and they observed all the rites customary at funerals, beating themselves and uttering lamentations. The second day was spent in merriment and feasting; because Adonis was allowed to return to life, and spend half of the year with Aphrodite. (Aristoph. Pax, 412, Schol. ad loc.; Plut. Alcib. 18, Nic. 13). For fuller particulars respecting the worship and festivals of Adonis, see Dict. of Biogr. s.v. Adonis.a
And Bill has added his own note:
a For a different set of references altogether, see Prof. Crosby’s note on the 62d Discourse of Dio Chrysostom.
But Dio reads:
On the contrary, it was his custom to slip away into the women’s quarters in his palace and there sit with legs drawn up on a golden couch, sheltered by purple bed-hangings, just like the Adonis who is lamented by the women ,…
and the note is:
5. As early as the fifth century Athenian women honoured him with a two-day festival in which the lament was prominent; cf. Aristophanes, Lysistrata 389. A celebration in Alexandria forms the background of Theocritus’ fifteenth idyl; cf. also Bion’s Lament in Edmonds, Greek Bucolic Poets (L. C. L.), pp386‑395.
Few sites indeed, other than Lacus Curtius, would give us so much for a few clicks.
Aristophanes, Lysistrata is here:
MAGISTRATE: Have the luxurious rites of the women glittered
Their libertine show, their drumming tapped out crowds,
The Sabazian Mysteries summoned their mob,
Adonis been wept to death on the terraces,
As I could hear the last day in the Assembly?
For Demostratus–let bad luck befoul him–
Was roaring, “We must sail for Sicily,”
While a woman, throwing herself about in a dance
Lopsided with drink, was shrilling out “Adonis,
Woe for Adonis.” Then Demostratus shouted,
“We must levy hoplites at Zacynthus,”
And there the woman, up to the ears in wine,
Was screaming “Weep for Adonis” on the house-top,
The scoundrelly politician, that lunatic ox,
Bellowing bad advice through tipsy shrieks:
Such are the follies wantoning in them.
MEN: O if you knew their full effrontery!
All of the insults they’ve done, besides sousing us
With water from their pots to our public disgrace
For we stand here wringing our clothes like grown-up infants.
This gives us little new information, tho.
Bion’s Lament for Adonis is here. However, while it makes clear that the festival was annual, it gives no indication as to when it took place.
The only remaining reference in that lot is the scholia on the passage in Aristophanes. I’m not at all sure, tho, where these might be found.
Next a search in Google books, which gave me Matthew Dillon, Girls and women in classical Greek religion. Page 164-5 talk of Menander’s Samia, much of which was recovered in 1907 from papyri, and more in 1959 in the Bodmer papyrus, giving us four out of five sections. This does not seem to be accessible online, however. Dillon tells us that the festival was not a state event, but conducted in private houses, a women-only event, including both respectable women and prostitutes involved, and he gives the Samia as his reference for this. But he also tells us that Photius mentions the Adonia (unfortunately I cannot see the footnote 155), as coming to the Greeks from Cyprus and Phoenicia. Interestingly he also says:
But Adonis was in no sense an eastern dying and reborn vegetation god. The Adonis images laid out as in death, and the seed garden that never bear fruit, honour him once each year. After the Adonia, he will not make an appearance until the next celebration of the festival (i.e. his death is commemorated each year; only late sources mention a resurrection).
On p.167-8 Dillon adds that the date of the festival is disputed. The Sicilian expedition referenced in Aristophanes was in early Spring in 415, but Plutarch gives the Adonia happening in the middle of a whole series of ill-omens before the expedition, all taking place in mid-summer. Two passages of Theophrastus say that the Gardens of Adonis were sown in the Spring. On p.168 he refers to, not one, but three decrees of the thiasotai (members of the thiasos), found at Piraeus.
All this is interesting. I wish I could see the references. The mention of Photius is perhaps a reference to the Lexicon, rather than the Bibliotheca.
There is also an entry in the Suda, although the online site doesn’t seem to allow us to link to articles. But it gives us nothing useful.
All of which is very inconclusive. I think we have to say, in truth, that we do not know for certain when the Adonia was celebrated.