Did You Know: The Tamrielic Calendar has varied drastically? In Arena and Daggerfall, all months were thirty days long. In Morrowind, there were only eleven months. Oblivion and Skyrim closely follow the Gregorian Calendar, except for leap years.
Additionally, Hearthfire, Midyear, and Frostfall are the only months that are a single word, but they are occasionally written in the more common two word style for the other months (Hearth Fire, Mid Year, and Frost Fall).