Commentary: The U.S. Shipping Peak Season That Wasn’t

In 2024, the U.S. shipping industry saw a dramatic shift in the traditional peak season patterns due to government-imposed tariff policies. While the public sentiment suggested there was no discernible peak season, the actual shipping data told a different story[para. 1][para. 2]. Despite initial perceptions, July’s seaborne import data showed a significant and unexpected surge in shipping volumes, which challenged previous assessments of the market’s performance this year[para. 3][para. 4].

The year began with traditional seasonality almost entirely overridden by tariff-driven behavior. In the first quarter, importers accelerated shipments to preempt tariffs implemented by the Trump administration. When tariffs began on April 2 and were then partially suspended on April 9—exempting all but China for 90 days—U.S. import volumes responded swiftly. By May, there was a 9.3% month-over-month drop in total seaborne imports, with shipments from China plummeting by 21%[para. 5]. However, after a subsequent 90-day suspension of tariffs on China announced on May 12, there was a short-lived spike in traffic from China late in May, seen in June as stabilization and a modest 1.8% rise in volume from China[para. 6].

The anticipation for a dramatic shipping boom during the tariff suspension led carriers, especially those on U.S. Southwest routes, to increase capacity beginning in late May. Despite these expectations, the expected shipping frenzy did not materialize, and both volume and freight rates seemed to slip into an off-season pattern throughout June and July. Many carriers even canceled extra sailings after adding capacity[para. 7].

Contrary to these market feelings, July saw the largest shock of the year: a robust 18% increase in total U.S. seaborne import volume month-over-month, translating into 400,000 additional TEUs, of which 300,000 came from China alone—a 43.3% surge for China month-over-month. China’s share of U.S. imports rebounded from around 31% in May and June to 38% in July. The July increase from Asia overall was 24%, driven primarily by China, with South Korea, India, Thailand, and Japan also showing substantial gains[para. 10]. Vietnam’s exports to the U.S., by contrast, remained stable throughout the period, demonstrating that major supply chain shifts are slow-moving and that, in the short term, only changes in China’s exports can deeply impact U.S. shipping volume[para. 11].

Despite the data, the perception of a non-existent peak season persisted. This was due to absolute volumes still being modest compared to pre-tariff periods; the rate of increase in July, when compared to March, was only 16%. As newly introduced shipping capacity outstripped demand, freight rates fell and the increased volume failed to create the typical intensity of peak season markets, especially on the trans-Pacific routes[para. 14].

Following the formal implementation of reciprocal U.S. tariffs on August 7 (with China’s tariffs again temporarily suspended), a period of relative stability and predictability returned to tariff policy, allowing importers to plan ahead for the rest of the year. However, as firms mostly completed their fall and winter shipments by mid-August, attention shifted to the next season, and the “invisible” peak period concluded in a subdued manner. With the true long-term impact of tariffs not fully realized until the fourth quarter, the industry now faces ongoing uncertainty—potentially peaking in 2026 as the aftereffects play out[para. 15][para. 16].