That's not surprising, given a series of storms that battered the East, especially the Southeast and major cities further north.
However, as weather improved in the second week, so did auto sales.
(Read more: Housing starts reel amid January freeze)
After 13 days, sales for the month were down just 1 percent, according to J.D. Power.
Analysts believe Presidents Day weekend and aggressive promotions will spur stronger business in the second half of February.
Customers paying more
The report on sales through midmonth shows customers continue to pay more for new cars, trucks and sport utility vehicles.
"The industry is on track to reach its highest-ever average transaction price for the month of February, with prices exceeding $29,000," Humphrey said. "This beats the previous record from February 2013 by more than $400."
(Read more: US cold snap's latest victim: Industrial output)
Furthermore, J.D. Power and LMC Automotive calculate total consumer spending on new vehicles will top $28.3 billion, an increase of $1.7 billion over last year.
(Read more: Small auto brands steal spotlight from big guys)
Still, despite the encouraging rebound in sales, the heavy inventory being carried by automakers remains a concern.
"While inventory levels are excessive at this point, demand during the spring selling season will help resolve the situation," said Bill Rinna, senior manager of forecasting at LMC Automotive. "However, if inventory is not cleared out by June, production levels in the second half of the year are at risk."
—By CNBC's Phil LeBeau. Follow him on Twitter @LeBeauCarNews.
Questions? Comments? BehindTheWheel@cnbc.com.