We know that retail sales move with the seasons, but what about e-commerce retail sales? FRED has the data, so we can take a look. The graph shows this series is also very predictable. The general trend is a straight line, with a pattern of increasingly large spikes in the fourth quarter. But e-commerce seasonal patterns are particularly striking: Retail sales in general always rise in the fourth quarter, but e-commerce sales do so even more intensely.

How this graph was created: Search for “E-Commerce” and select the “Sales Share” series without seasonal adjustment.

Suggested by Christian Zimmermann