Calendar

Tariek is a planet has a similar rotational cycle and calendar to earth, and she has but one moon. There are 13 months, each with 28 days, so split perfectly as the 7 day weeks, the lunar cycle. The moon is inherently important culturally across the world. The months are named below, in order of when the year is marked as starting. The seasons listed are referencing Valerick, the largest by landmass, continent. Ryna, in the same hemisphere as Valerick, follows the same calendar seasonally. For Gratos, the seasons are inverted. Months that are listed as winter are summer, spring becomes autumn, summer becomes winter, and autumn becomes spring.
Jundar: New year, Winter
Fenrok: Winter
Halan: Winter
Agun: Spring
Borin: Spring
Camor: Spring
Tovanna: Summer
Acrom: Summer
Gont: Summer
Tigre: Autumn
Fosta: Autumn
Heva: Autumn
Menata: Winter

Then of course there are seven days to each week, 24 hours in each 'daily' cycle. The Days of the week are listed below, with real world comparison for purposes in case it would help anyone like it does me.
Day...............Real World Equivalent
Sundance............Sunday
Lunai..................Monday
Demairt..............Tuesday
Ceadaoin.............Wednesday
Deardaoin............Thusday
Aoine..................Friday
Saturnalian..........Saturday
Each nation may have its own holy days or 'holidays' they celebrate, but some are universal, nation, continent and even worldwide. They may celebrate different things because of the seasonal difference, as will be shown on the table below, but these eight days are the celebrated holy days. They are listed below.

Date....................Valerick and Ryna Celebration..........................Gratos Celebration
1st of Jundar...........Winter Solstice/New year..................................Summer Solstice
1st of Fenrok...........Imbolc/Turning point of winter...........................Imbolc/Summer Farewell
14th of Agun...........Ostara/Planting Season....................................Ostara/First Harvest
24th of Camor.........Beltaine/Welcoming of Summer........................Beltaine/Second Harvest, Welcoming Winter
14th of Acrom.........Lammas/Summer Solstice................................Lammas/ Winter Solstice/New Year
1st of Tigre.............Lughnasad/Summer's End................................Lughnasad/End of Winter
1st of Fosta..........Mabon/First Harvest..........................................Mabon/Celebration of planting season
1st of Menata..........Samhain/Second Harvest, Welcoming Winter...Samhain/Welcoming Summer

Manifestation