The word "almanac" is of uncertain medieval Arabic origin; in modern Arabic a similar word means weather. Weather-related lore and predictions are still found in almanacs, as well as calendars of the days, weeks, and months of the year, a record of astronomical phenomena, and seasonal advice for farmers and gardeners. They also provide data on the rising and setting times of the sun and moon, the phases of the moon and the positions of the planets.

Growers in eighteenth and nineteenth century America relied heavily on these inexpensive and ubiquitous guides, particularly those who followed the age-old belief that the moon and planets influenced the germination and growth of all plants. This is a tradition that has never died out. Today there are still gardeners who use special lunar and astrological calendars for all garden chores.