(TNND) — Imports hit an early peak this year ahead of expected sharp drops in shipments under the weight of President Donald Trump’s tariffs, according to a new Global Port Tracker report from the National Retail Federation and Hackett Associates.

Hackett Associates partner Daniel Hackett said August is usually the peak of import volume as retailers prepare for the holidays.

“But this year, certainly, July is the peak,” he said. “And then we’ll see a decline through the rest of the year in each subsequent month. I mean, that’s tariff-related, it’s this pull forward of cargo.”

Importers are trying to bring in as much merchandise as possible in windows of lower tariffs, which may be kept open a bit longer with Trump’s 90-day negotiating extension with China.

July was the second-busiest importing month on record and a roughly 20% increase from June.

Hackett Associates, a maritime trade and supply chain consulting firm, is forecasting small yearly declines in import volume for August and September, followed by larger yearly declines in October, November and December.

“Most of what needed to be here is already here” for the holidays, Hackett said.

Both November and December are forecasted to see yearly drops of about 20%.

But Hackett said forecasting trade volume is tricky with the fast-moving nature of Trump’s trade policy.

His full-year forecast is for a 3.4% decline in imports, which would buck the trend of rising import volume year after year.

The scope of decline isn’t a big deal, coming off a big increase, about 15%, last year.

But the shape of import activity this year was unique and clearly impacted by tariffs, Hackett said.

The Yale Budget Lab said the effective tariff rate has increased from 2.4% at the start of the year to 17.4% now.

It’s now the highest since 1935.

Hackett said importers are not only dealing with higher costs, but they’re also trying to navigate uncertainty in the trade policy.

“And so that does make things very hard to predict,” Hackett said. “And that uncertainty is definitely a negative, not just on the forecasting, but on the economy, as well. It makes it very hard for businesses to consider capital investments, or for importers to determine when it is that they should be bringing in their cargo.”

Larger businesses have more ability to be nimble with their supply chains, he said. Small businesses are having a tougher time.

But retailers of all sizes have pulled forward inventory to blunt the impact of tariffs.

“These tariffs and disruptions to the supply chain are adding costs that will ultimately lead to higher prices for American consumers,” NRF Vice President for Supply Chain and Customs Policy Jonathan Gold said in a news release.

Meanwhile, the Supreme Court has agreed to hear arguments over Trump’s tariffs.

“I wish I had the foresight to be able to know which way they’re going to rule,” Hackett said. “I think that just adds to the uncertainty.”