It was a weird summer.

That is, in terms of vehicle demand and prices.

Stemming from concern over potential tariffs on vehicles and car parts that pulled demand forward, Cox Automotive chief economist Jonathan Smoke said in a conference call with reporters this week that June, July and August were the best months so far this year for new- and used-car sales.  

(And in an email followup, Smoke said he also projects, “that from a retail sales SAAR perspective, the summer months will also likely end up being the best for the year once all is said and done.”)

Cox Automotive had conducted a survey with Morning Consult in August that discovered three-quarters of car owners worried over such tariffs, and that vehicle-shopping plans were affected among more than half of the buyers in the study, thanks to news around these tariffs.

“We also saw 11 straight weeks of used-vehicle price appreciation, also extremely unusual for this time of year,” Smoke said during the conference call . “That price appreciation aligned with faster moving inventory and the retail and wholesale markets, so we know that it was demand driven.”

Cox Automotive believes the “abnormal” pull-ahead behavior could be winding down soon, as September began to show signs of the seller’s market waning, Smoke said.

“Kelley Blue Book’s average transaction prices were flat in September compared to August,” he said. “It will definitely be interesting to see how incentives come in when we get all of the data on the new-vehicle side this month.

“We release the Manheim index for September on Friday, but I can share that weekly Manheim metrics we track show that depreciation has normalized over the last several weeks, so that strange period of appreciation has definitely ended.”

Additionally, Smoke noted how higher interest rates are causing a drop in the “would-be buyer pool” in the new-vehicle market.

“The used market demand pool has grown as a result, but the supply going forward is going to be limited in the used-vehicle market,” Smoke said.

“So, we now have this situation where we've had several years of supply growing in the used market,” he said. “And now we're starting to see some challenges on that front, likely leading to fewer used sales or certainly no longer growth in the future.”

As for September, used-car retail sales were expected to slide a bit from August, but the seasonally adjusted annualized rate remains near 40 million units.

Edmunds was forecasting used-car sales of 3.3 million for September, which would be down from 3.4 million in August. The resulting SAAR would be 39.6 million, down from 39.7 million a month ago, the firm said.