An almanac is a book published every year that collects useful facts, predictions, and information about the coming year. Traditional almanacs include calendars, weather forecasts, sunrise and sunset times, moon phases, planting advice for farmers, and tide tables for sailors. Some almanacs also feature jokes, recipes, and interesting facts.

The most famous American almanac is probably Poor Richard's Almanack, which Benjamin Franklin published in colonial times. Franklin filled his almanac with clever sayings like “early to bed and early to rise makes a man healthy, wealthy, and wise.” His almanac became so popular that nearly every colonial household owned a copy.

Today, almanacs still exist both as books and websites. The Old Farmer's Almanac has been published continuously since 1792, making it one of America's oldest publications. Modern almanacs might include sports statistics, historical facts, population data, and records of major events from the previous year.

In earlier times, astronomers created detailed charts predicting celestial events, and almanacs became especially important before radio, television, and the internet, when people relied on these annual books for practical information they couldn't easily get anywhere else. Even now, many people enjoy consulting an almanac to see its long-range weather predictions (sometimes surprisingly accurate) or to look up when the next full moon will occur.