The various ancient Greek calendars began in most states of ancient Greece between Autumn and Winter except for the Attic calendar, which began in Summer.
The Greeks, as early as the time of Homer, appear to have been familiar with the division of the year into the twelve lunar months but no intercalary month Embolimos or day is then mentioned. Independent of the division of a month into days, it was divided into periods according to the increase and decrease of the moon. Thus, the first day or new moon was called Noumenia. The month in which the year began, as well as the names of the months, differed among the states, and in some parts even no names existed for the months, as they were distinguished only numerically, as the first, second, third, fourth month, etc.
Of primary importance for the reconstruction of the regional Greek calendars is the calendar of Delphi, because of the numerous documents found there recording the manumission of slaves, many of which are dated both in the Delphian and in a regional calendar.
The months of the Aetolian calendar have been presented by Daux (1932) based on arguments by Nititsky (1901) based on synchronisms in manumission documents found at Delphi (dated to the 2nd century BC). The month names are:
The intercalary month was Dios, attested as Dios embolimos in SEG SVI 344, equivalent to Delphian Poitropoios ho deuteros. The month Boukatios corresponds to Delphian Daidaphorios, while Delphian Boukatios is Aetolian Panamos.
See Attic calendar
The Corinthian months and their order is known from the sequence on the dial of the Antikythera mechanism
A number of Locrian calendars are recorded, but only from the 2nd century BC. The Ozolian Locris for practical reasons also had a federal calendar which simply enumerated months from one to twelve. The first month (Protos) corresponds Delphian Boukatios, and the remaining months correspond in sequence to the regular sequence of Delphian months. Separate month names are recorded from the Locrian cities of Amphissa, Physkos, Oianthea, Tritea and Tolophon.
on the Rhodian calendar
The Thessalian calendar was standardised only in the Roman era. Previously, all poleis had their own calendars based on their respective festivals.