Source: Port Authorities. Note: The grey area represents one standard deviation from the average.
As a derived demand, container traffic is subject to seasonal fluctuations due to retail and manufacturing cycles. Generally, the peak season of port activity is between May and November, and the through season is between December and March, with February being the month of lowest activity. Retail cycles are particularly important as sales are more pronounced in the last trimester of the year (e.g., Thanksgiving and Christmas). So, goods must be procured and carried a few months in advance, particularly for Asia-Europe and transpacific trades.
Ports usually handle 26% of their annual traffic during the peak months of August to October and 23% of their annual traffic from December to February. This pattern is evident for a major commercial gateway and having deep hinterland connections, such as Los Angeles and New York. The low February volume for Shanghai is associated with the Chinese New Year and the slowdown in industrial activity (and exports). Transshipment hubs are subject to less volatility (or have more traffic stability) since they connect multiple shipping networks and regional markets. Seasonality impacts port infrastructure and operations since it requires investments to handle the peak demand, but must account for lower revenues during the through periods.