Thedas Calendar

"Each month has a High Name (the original, official Imperial name used primarily by courts and scholars) and a Low Name (the name used by commoners and merchants) and an even 30 days."
 
: Annum: First Day: The beginning of the year, this holiday traditionally involves many visits to one's neighbors and family (this was once to "check" to make sure everyone was alive at least once a year in remote parts) and a town gathering to commemorate the year past (often accompanied by much drinking and merriment).
First Month: Wintermarch (low, common name), Verimensis (high name).
: Annum: Wintersend: Once called "Urthalis" and dedicated to Urthemial, the Old God of beauty, this holiday has traditionally become a celebration of the Maker. It stands for the end of winter in many lands and often coincides with tourneys and contests that conjure the Proving Grounds in Minrathous (which always has its biggest contests on this day). In most southern lands, this holiday has become a day of gathering for trade, theater, and (in some areas) the arrangement of marriages.
Second Month: Guardian, Pluitanis.Third Month: Drakonis, Nubulis.Fourth Month: Cloudreach, Eluviesta.
: Annum: Summerday: Once called "Andoralis" and dedicated to Andoral, the Old God of chains, this holiday is universally celebrated as the beginning of summer, a time for merriment and marriages to take place. Traditionally, boys and girls who are ready to come of age participate in a grand procession in which they cross the settlement in white tunics and gowns and end up at the local Chantry; there they are advised on the responsibilities of adulthood. This is considered a very holy day in Orlais.
Fifth Month: Bloomingtide, Molioris.Sixth Month: Justinian, Ferventis.Seventh Month: Solace, Solis.
: Annum: Funalis: This holiday was once dedicated to the Old God of silence, Dumat. Since Dumat's rise during the First Blight, however, this fact has been largely ignored. Now the holiday is invariably known as All Soul's Day and is supposed to be spent in somber remembrance of the dead. In some northern lands, it is traditional for the population to dress as spirits and walk the streets in parade after midnight. The Chantry has co-opted this holiday to remember the death of Andraste, with fires that mark her burning appearing throughout the community. Plays depicting the tale of her death are also quite common.
Eighth Month: August, Matrinalis.Ninth Month: Kingsway, Parvulis.Tenth Month: Harvestmere, Frumentum.
: Annum: Satinalia: In many places, this holiday—once dedicated to the Old Goddess of chaos, Zazikel, but now attributed more to the Second Moon, Satina—is still accompanied by wild celebration. Celebrants wear masks and lose their inhibitions, and they place the town fool as ruler for a day. In Antiva (Antiva City in particular), this festival lasts for a week or more, followed by a week of fasting. In more pious areas, this holiday is now marked by large feasts and gift-giving.
Eleventh Month: Firstfall, Umbralis.Twelfth Month: Haring, Cassus.
-- Source: Prima Strategy Guide for Dragon Age: Origins.