Almanac is an in-game book that contains data on a variety of topics, such as a yearly weather forecast, instructions on how long it takes crops to develop, local announcements like holidays and birthdays, and even updates from the Adventurer's Guild. It also provides detailed information about each of the twelve months. The information in Almanac is useful for farmers and adventurers, and the book is updated regularly with new information. You can open the book from your inventory or press the hotkey F7 to open it. You can then just pick a page and explore. The book is built into the game, so you don't have to download anything extra.