Assuming that we’re given the months in their proper order the Olbian calendar breaks down as follows:

Taureon: April/May
Thargelion: May/June
Kalamaion: June/July
Panemos: July/August
Metageitnion: August/September
Boedromion: September/October
Kuanepsion: October/November
Apatourion: November/December
Poseideon: December/January
Leneon: January/February
Anthesterion: February/March
Artemision: March/April

Andokides does not provide a name for the intercalary month; if I were going to use this instead of the Bakcheion calendar I’d call it “Lykeion.” 

My reasoning for this: 

• Since there is a Bull Month (Taureon) it’s only fitting to have a Wolf Month. 
• Apollon doesn’t have as much representation on the calendar as he probably should, considering his prominence in the Olbian pantheon. He appears on the city’s coinage, he’s mentioned in city treaties, the majority of the temples that have been uncovered thus far belong to him, he had several distinct forms i.e. Apollo Delphinios (of Delphi), Apollo Ietros (Healer), Apollo Neomenios (he who Opens the Month), Apollo Boreas (of the North Wind) etc, and there were several private religious associations dedicated to him – including one with possible Orphic ties.
• It just feels right. 

Most of the names are familiar from other Greek calendars, but Kalamaion and Kúanepsion were new to me;  I’m uncertain of their meaning. 

There is a Púanepsion in the Attic calendar, from the Púanopsia (Bean-stewing) festival Theseus instituted in fulfillment of a vow he swore to Apollon should he prove victorious against the Minotaur. It is the seventh month. 

However, I checked the Greek and it is clearly a Kappa heading that word. Assuming that the person chiseling the inscription didn’t just fuck things up Kúanepsion could come from kúanos (κῠᾰνος) “dark blue” which, ironically enough, Robert Beekes’ Etymological Dictionary of Greek says probably derives from Hittite kuwannan (precious stone, copper, blue), likely from Proto-Indo-European *ḱwey- (to shine, white, light; compare *ḱweytós, white.) Ironic because there’s that whole debate about whether the ancients could even see blue. 

This begs the question of why they’d name one of their months Dark Blue – unless it’s from Kyanê (Κυανη), one of the Sicilian Nymphs who were part of Kore’s maiden companions that were out collecting flowers with her when the abduction occured:  

A great fountain was made sacred to Persephone in the territory of Syrakousa and given the name Kyane or ‘Azure Font.’ For the myth relates that it was near Syrakousa that Plouton effected the rape of Kore and took her away in his chariot, and that after cleaving the earth asunder he himself descended into Haides, taking along with him the bride whom he had seized, and that he caused the fountain named Kyane to gush forth, near which the Syrakousans each year hold a notable festive gathering; and private individuals offer the lesser victims, but when the ceremony is on behalf of the community, bulls are plunged in the pool, this manner of sacrifice having been commanded by Herakles on the occasion when he made the circuit of all Sicily, while driving off the cattle of Geryones. (Diodoros Sikeliotes, Library of History 5.2.3)

While Herakles as the progenitor of the Skythians was certainly popular in the region and there was a temple to the Eleusinian deities at Olbia, the Azure Font is a local Syracusan addition to Persephone’s story. Olbia had extensive trade relations with a number of cities in Magna Graecia so it’s entirely possible that they were aware of the myth, but why enshrine it in their calendar? 

I’m not sure what else it could be though. 

As for Kalamaion only a couple things occur to me. 

Perhaps it honors the Epiriote River God Kalamas who flows into the Ionian Sea – but what significance would that have to a Milesian colony all the way over in the Ukraine?

Now the Kala- part could come from kalós (καλός) meaning:

• beautiful, lovely
• good, quality, useful
• right, moral, virtuous, noble

I don’t know all the rules of declension and word formation so I’m not sure if that’s sufficient to explain the name, but the second half reminds me of Μαῖα the mother of Hermes as well as μαία meaning nurse or midwife. 

Comparing the Olbian calendar to others in the Greek world it probably comes the closest to the Attic, despite beginning shortly after the Spring Equinox whereas in Athens this happened post Summer Solstice. 

Taureon = Mounichion*
Thargelion = Thargelion
Kalamaion = Skiraphorion
Panemos = Hekatombaion
Metageitnion = Metageitnion
Boedromion = Boidromion
Kuanepsion = Puanepsion
Apatourion = Maimakterion
Poseideon = Poseideon
Leneon = Gamelion*
Anthesterion = Anthesterion
Artemision = Elaphebolion*

I’ve bolded matching months and put asterisks on ones with possible equivalences.

Mounichion, for instance, is the month in which the Mounichia took place. The festival takes its name from an epiklesis of Artemis associated with a temple in the Piraeus, Athens’ famous harbour district. The festival both celebrated the birthday of the Goddess and commemorated the Battle of Salamis, during which she favorably intervened on behalf of the Athenians. There was a procession in which young girls who played the part of Bears and served the Goddess at her sanctuary in Brauron took part. Cakes encircled with candles and other sacrifices were given on this occasion. 

While Taureon most likely means the Month of the Bull (as it does in other calendars) and honors Dionysos whose bull form was especially prominent in Asia Minor (and the Pontic region in particular) it could also refer to the Taurike, a region along the southern coast of the Crimean peninsula whose capital Tauris was home to a particularly savage form of Artemis (or her Skythian equivalent) which engaged in human sacrifice. Iphigéneia became her high priestess, after nearly being sacrificed herself at Aulis. Orestes rescues his sister, and is directed to steal the xoanon or primitive wooden idol of Artemis and take it to the town of Halae, where he is to build a temple for Artemis Tauropolos (Bull-slayer.) The xoanon either ends up in Sparta where it is worshiped with rites of bloody flagellation as Artemis Orthia or Italy where the Rex Nemorensis or King of the Grove served her until his successor came along and murdered him. Iphigéneia ended her days at the Brauron sanctuary where she taught the maidens the mysteries of the Bear Dance. 

Although in Attica the seventh month is Gamelion, after the hieros gamos (sacred marriage) of Zeus and Hera, in other parts of Greece the period of January/February (particularly in Asia Minor) is called some variation of Lenaeon from the Lenaia festival. 

Although not called Artemision as in Olbia, the Attic Elaphebolion honors Artemis the Deer Slayer at whose festival the Elaphebolia cakes in the shape of deer were offered. This either celebrated her hunting prowess, the transformation of Iphigéneia into a deer to save her from Agamemnon’s blade or the defeat of the Thessalians by Athens and Phokis thanks to another miraculous intervention by Artemis.

Panemos and its dialectical variations are found on the calendars of Aetolia, Argolis, Boiotia, Epidauris, Laconia, Rhodes. Sicily, Thessaly and the Makedonian-derived systems, among others. 

Apatourion has two possible origins. Either from the Apatouria festival, which the Wiley Online Library describes as follows:

The Apatouria, an important festival celebrated by Ionians, including Athenians, was for Herodotus one of two criteria of Ionian identity (Hdt. 1.147). In Athens the Apatouria was the central element in the ritual calendar of the phratries, the kinship organizations crucial for determining Athenian citizenship. The three‐day festival occurred in the autumn in the month Pyanepsion and was celebrated at the separate phratry shrines throughout Attica. There was a feast on the first day, and a sacrifice to Zeus Phratrios and Athena Phratria on the second. On the third day, fathers would introduce their sons for admission to the phratry (and, in effect, to Athenian citizenship). In the normal course of events this occurred during a child’s first few years. Our sources suggest that there were various athletic and intellectual literary competitions over the three days in which the children of the phrateres could demonstrate their merit. Ancient scholarship links the Apatouria to the myth of the ritual combat between the Athenian Melanthos (the “dark one”) and the Boiotian Xanthos (the “fair one”) for the kingship of Attica, which Melanthos won through a trick (apate) (Hellanikos FGrH 4 F23). Although some modern scholars have therefore seen a connection to the ephebes and to rites of passage involving social inversion, the rituals of the festival have no apparent connection to the narrative of the myth, and most modern scholars now link the Apatouria to “the control, maintenance, and affirmation of kinship and of membership in society at every level” (Lambert 1993: 151).

This trick or apate was played by none other than Dionysos:

The Athenians had a war on against the Boiotians over Kelainai, which was a place in their borderlands. Xanthios, a Boiotian, challenged the Athenian king, Thymoites to a fight. When he did not accept, Melanthos, an expatriate Messenian from the stock of Periklymenos the son of Neleus, stood up to fight for the kingdom. While they were engaged in single combat, someone wearing a black goat-skin cape appeared to Melanthos from behind Xanthios. So Melanthos said that it was not right to come two against one. Xanthios turned round and Melanthos smote and killed him. And from this was generated both the festival Apatouria and ‘of the Black Aigis’ as an epithet of Dionysos. (Suidas s.v. Apatouria)

However, it’s equally possible that the name comes from the epiklesis Mistress of Apatouron borne by Aphrodite Ourania in the Bosporus, for which Strabo gives the following aition:   

There is also in Phanagoreia a notable temple of Aphrodite Apaturus. Critics derive the etymology of the epithet of the Goddess by adducing a certain myth, according to which the Giants attacked the Goddess there; but she called upon Herakles for help and hid him in a cave, and then, admitting the Giants one by one, gave them over to Herakles to be murdered through “treachery.” (11.2.10)

For more on this Goddess, check out Yulia Ustinova’s Aphrodite Ourania of the Bosporus: The Great Goddess of a Frontier Pantheon.