SANTA MONICA, Calif. — New-car buyers flocked to dealerships for Labor Day weekend sales but have largely stayed away since then, according to Edmunds.com.

“New-car sales for the three-day weekend jumped a remarkable 22 percent compared to average weekend sales in August, rather than the typical 12 percent rise,” said Edmunds.com Senior Analyst Ray Zhou. “But as soon as the holiday weekend was over, car-shopping activity fell about 40 percent.”

The automotive industry is currently tracking at an 11.3 million seasonally adjusted annual rate for September, assuming slightly lower fleet sale volume than last month, said Edmunds.com analysts.

So far this month, BMW, Chrysler, Ford and Volkswagen retail sales are down between five and ten percent compared to the first two weeks of August, while Nissan is up about five percent and Toyota is up about nine percent. The rest of the automakers are relatively stable.

“Labor Day occurred unusually late this year. This took some sales that would normally have occurred in late August in the run up to the Labor Day weekend and pushed them fully into September,” wrote Edmunds.com CEO Jeremy Anwyl in his blog, “Just to Clarify.”

“There are no more holiday weekends in September and few throughout the rest of the year, so automakers may want to think about some creative ways to stimulate sales. Momentum seems to be lacking whenever the calendar does not reflect a traditional sales period,” commented Edmunds.com Senior Analyst Jessica Caldwell.