What is indicated by a repeating pattern in a time series plot?

A repeating pattern in a time series plot indicates a seasonal pattern. This type of pattern reflects regular and predictable fluctuations that occur at specific intervals, often tied to seasonal changes, such as seasons of the year or specific time periods (like months or quarters). For instance, retail sales may increase during the holiday season every year, reflecting this seasonal behavior.

In time series analysis, recognizing seasonal patterns is crucial for forecasting and making decisions based on expected future behaviors. These patterns are distinct because they repeat consistently, as opposed to trends which indicate a long-term movement in one direction or cycles which represent fluctuations that can be longer and less predictable than seasonal changes. Irregular patterns are random and do not have a consistent repeatable nature. Thus, identifying seasonal patterns helps analysts understand and prepare for regular variations in data associated with time.