Calendar

There are 12 months in a year. They are: There are a number of different holidays that are celebrated throughout Tamriel during these months. In the first, two Elder Scrolls games, several of these holidays would result in different benefits being offered on these days.
 * Morning Star
 * Sun's Dawn
 * First Seed
 * Rain's Hand
 * Second Seed
 * Mid Year
 * Sun's Height
 * Last Seed
 * Heartfire (Sometimes "Hearthfire")
 * Frostfall
 * Sun's Dusk
 * Evening Star.

Morning Star
Morning Star is the first of the 12 seasons in the Elder Scrolls universe. It is considered to be a Winter month. (by our definition). It is homologous to January.

Annual Events during Morning Star:

 * 1) 1st of Morning Star: New Life Festival celebrated in Tamriel.
 * 2) 2nd of Morning Star: Scour Day celebrated in many High Rock cities.
 * 3) 12th of Morning Star: Ovank'a is celebrated in the Alik'r Desert. It is a holiday to Stendarr.
 * 4) 15th of Morning Star: South Wind's Prayer celebrated in Tamriel
 * 5) 16th of Morning Star: Day of Lights celebrated in Hammerfell. It is a prayer for good farming and fishing for the upcoming year.
 * 6) 18th of Morning Star: Waking Day (Breton Holiday) held, particularly amongst the peoples of the Yeorth Burrowland

Sun's Dawn
Sun's Dawn is the second of the 12 seasons in the Elder Scrolls universe. It is considered to be a Winter month. (by our definition).

Annual Events during Sun's Dawn:

 * 1) 2nd of Sun's Dawn: Mad Pelagius day is celebrated. (Breton Holiday). It is often boasted that it was his time in High Rock that drove him mad.
 * 2) 5th of Sun's Dawn: Othroktide (Breton Holiday), celebrated to honor the first Baron of Dwynnen.
 * 3) 8th of Sun's Dawn: Day of Release celebrated in Glenumbria Moors to signify the victory of Aiden Direnni over the Alessian Order in a battle here.
 * 4) 16th of Sun's Dawn: Heart's Day is celebrated throughout Tamriel. (Note: Strong similarities to Valentine's Day) 
 * 5) 27th of Sun's Dawn: Perseverance Day celebrated in Ykalon, to celebrate the death of those who fought against the Camoran Usurper.
 * 6) 28th of Sun's Dawn: Aduros Nau celebrated in Hammerfell.

First Seed
First Seed is the third of the 12 seasons in the Elder Scrolls universe. It is considered to be a Spring month. (by our definition).

Annual Events during First Seed:

 * 1) 7th of First Seed: First Planting celebrated across Tamriel: A time to set asite past differences and to begin anew.
 * 2) 9th of First Seed: Day of Waiting celebrated in several towns and cities in the Dragontail Mountains.
 * 3) 21st of First Seed: Hogithum is celebrated by the Dunmer priests, who call upon Azura for guidance and support.
 * 4) 25th of First Seed: Flower Day (Breton Holiday) is celebrated in some of the smaller towns in the High Rock region.
 * 5) 26th of First Seed: Festival of Blades held in the Alik'r Desert.

Rain's Hand
Rain's Hand is the fourth of the 12 seasons in the Elder Scrolls universe. It is considered to be a Spring month. (by our definition).

Annual Events during Rain's Hand:

 * 1) 1st of Rain's Hand: Gardtide (Breton holiday) celebrated in Tamarilyn Point
 * 2) 13th of Rain's Hand: Day of the Dead celebrated (Breton holiday).
 * 3) 20th of Rain's Hand: Day of Shame celebrated in Hammerfell
 * 4) 28th of Rain's Hand: Jester's Day festival held all over Tamriel

Second Seed
Second Seed is the fifth of the 12 seasons in the Elder Scrolls universe. It is considered to be a Spring month. (by our definition).

Annual Events during Second Seed:

 * 1) 1st of Second Seed: Rite of Vigyld practiced by the Psijic Order
 * 2) 7th of Second Seed: Second Planting is celebrated.
 * 3) 9th of Second Seed: Maruk's Day is held, celebrating the life of First Era prophet Marukh. (Breton Holiday)
 * 4) 20th of Second Seed: Fire Festival is held in the Northmoor region.
 * 5) 30th of Second Seed: Fishing Day (Breton Holiday), where those in the Iliac Bay region who survive on Fishing for a living celebrate.

Mid Year
Mid Year is the sixth of the 12 seasons in the Elder Scrolls universe. It is considered to be a Summer month. (by our definition).

Annual Events during Mid Year:

 * 1) 1st of Mid Year: Drigh R'Zimb (Traditional Redguard holiday). Now, only celebrated in Abibon-Gora
 * 2) 16th of Mid Year: Mid Year Celebration is held.
 * 3) 23rd of Mid Year: Dancing Day is celebrated in Daggerfall.
 * 4) 24th of Mid Year: Tibedetha (Breton Holiday) - translates as "Tiber's Day". Celebrated in honor of Alcaire's most famous son, Tiber Septim.

Sun's Height
Sun's Height is the seventh of the 12 seasons in the Elder Scrolls universe. It is considered to be a Summer month. (by our definition).

Annual Events during Sun's Height:

 * 1) 10th of Sun's Height: Merchants' Festival is held, every shop owner except the Mages Guild traditionally lowers their prices by at least half.
 * 2) 12th of Sun's Height: Divad Etep't festival held in Antiphyllos, to celebrate the deeds of Divad.
 * 3) 20th of Sun's Height: Sun's Rest festival held.
 * 4) 29th of Sun's Height: Fiery Night festival is held in the Alik'r Desert

Last Seed
Last Seed is the eighth of the 12 seasons in the Elder Scrolls universe. It is considered to be a Summer month. (by our definition).

Annual Events during Last Seed:

 * 1) 2nd of Last Seed: Day of Maiden Katrica celebrated in Ayasofya, to show their appreciation of a warrior that saved them.
 * 2) 11th of Last Seed: Koomu Alezer'i (Redguard Festival). In Sentinel, this is now considered to be a harvest thanksgiving.
 * 3) 14th of Last Seed: Feast of the Tiger held in the Bantha region. (Redguard holiday).
 * 4) 21st of Last Seed: Appreciation Day held in Anticlere. A holiday devoted to Mara
 * 5) 27th of Last Seed: Harvest's End holiday is held.

Heartfire
Heartfire is the ninth of the 12 seasons in the Elder Scrolls universe. It is considered to be a Fall (Autumn) month. (by our definition).

Annual Events during Hearthfire:

 * 1) 1st of Hearthfire: The Rites of Moawita practiced by the Psijic Order.
 * 2) 3rd of Hearthfire: Tales and Tallows - A celebration of Necromancy. Many citizens fear this day, and avoid the streets
 * 3) 6th of Hearthfire: Khurat is celebrated in the Wrothgarian Mountains
 * 4) 12th of Hearthfire: Riglametha held in Lainlyn.
 * 5) 19th of Hearthfire: Children's Day celebrated in Betony.

Frostfall
Frostfall is the tenth of the 12 seasons in the Elder Scrolls universe. It is considered to be a Fall (Autumn) month. (by our definition).

Annual Events during Frostfall:

 * 1) 5th of Frostfall: Dirij Tereur celebrated in the Alik'r Desert.
 * 2) 13th of Frostfall: Witches's Festival celebrated in Tamriel. It is the day when the forces of Sorcery and Religion clash.
 * 3) 23rd of Frostfall: Broken Diamonds celebrated in Tamriel. The day on which, in 3E 121 when Kintyra II was killed in Glenpoint (Referenced in Daggerfall).
 * 4) 30th of Frostfall: Emperor's Birthday celebrated

Sun's Dusk
Sun's Dusk is the eleventh of the 12 seasons in the Elder Scrolls universe. It is considered to be a Fall (Autumn) month. (by our definition).

Annual Events during Sun's Dusk:

 * 1) 3rd of Sun's Dusk: Serpent's Dance (Redguard Holiday) celebrated in Satakalaam.
 * 2) 8th of Sun's Dusk: Moon Festival (Breton Holiday), celebrated on this day in Glenumbria Moors.
 * 3) 18th of Sun's Dusk: Hel Anseilak (Redguard Holiday). The most serious of holidays for the Pothago people.
 * 4) 20th of Sun's Dusk: Warriors Festival: Throughout Tamriel, Armorers and Blacksmiths sell their products at half price.

Evening Star
Evening Star is the final month of the 12 seasons in the Elder Scrolls universe. It is considered to be a Winter month. (by our definition).

Annual Events during Evening Star:

 * 1) 15th of Evening Star: North Wind's Prayer celebrated
 * 2) 18th of Evening Star: Baranth Do is celebrated (Redguard festival). It is a New Year's Festival
 * 3) 24th of Evening Star: Chil'a is celebrated. (Redguard festival).
 * 4) 25th of Evening Star: New Life Festival celebrated. It is a holiday originally celebrating debauchery, but has since come to be recognised as a day for gift giving and parties. (Note: Similar to Christmas)
 * 5) 30th of Evening Star: Old Life celebrated

References:
http://www.imperial-library.info/content/calendar-tamriel