Fishing almanacs assign a color code to the overall fishing quality of a day to designate good, fair or poor fishing. There is typically a separate column suggesting the ideal time of a particular day to fish.
Fishing almanacs determine the best days and specific times for fishing using calculations based on the solar and lunar cycles. These guides take into consideration the timing of the rising and setting of the moon, as well as the timing of high and low tides, as this is often when fish are most likely to feed. Fish also tend to be more active during a full moon, when tides are higher than average and feeding is typically more successful. A good almanac provides an overall rating for a day and designates a time that fishing is most likely to be the most successful within that day.
Regional tides and weather affect fishing, so it is best to also take into consideration local conditions when consulting a fishing almanac. For example, fish are more likely to bite when the water is still or even rippled, but not during a strong wind. They are also more active when atmospheric pressure is steady or on the rise. A northern or eastern wind typically deters fish, but fish are typically active during a breeze from the west.