"Retailers are carefully managing their inventories but still need to stock up on seasonal goods for spring and summer," said NRF Vice President for Supply Chain and Customs Policy Jonathan Gold. "Comparisons with last year are difficult because of the surge of cargo after problems at West Coast ports ended, but we think consumers will continue to increase their spending this year and retailers will be ready."

Ports covered by Global Port Tracker handled 1.43 million twenty-foot equivalent units in December, the latest month for which after-the-fact numbers are available. With most holiday merchandise already in the country by that point, volume was down 3.4 percent from November and 0.8 percent from the year before. That brought 2015 to a total of 18.2 million TEU, up 5.3 percent from 2014. One TEU is one 20-foot-long cargo container or its equivalent.

January was up an estimated 18.3 percent over 2015 at 1.46 million TEU, but the percentage was skewed unusually high because of weak volume seen last year just before agreement on a contract with West Coast dockworkers ended months of congestion. February is forecast at 1.39 million TEU, up 16.2 percent, also skewed by the congestion. March is forecast at 1.35 million TEU, down 22.4 percent from high levels seen when a flood of backlogged cargo followed the contract agreement. Patterns are expected to return closer to normal in April, which is forecast at 1.49 million TEU, down 1.2 percent from last year. May is forecast at 1.57 million TEU, down 2.6 percent, and June at 1.55 million TEU, down 1.2 percent. The first half of 2016 is expected to total 8.8 million TEU, up 4.5 percent over 2015.

Global Port Tracker, which is produced for NRF by the consulting firm Hackett Associates, covers the U.S. ports of Los Angeles/Long Beach, Oakland, Seattle and Tacoma on the West Coast; New York/New Jersey, Hampton Roads, Charleston, Savannah, Port Everglades and Miami on the East Coast; and Houston on the Gulf Coast.

Source: NRF