Several segments contributed to May's jackpot of about 164,000 extra units. Besides the stellar compact and premium crossover categories, compact and subcompact cars slightly outperformed the market. Full-sized vans surged 29 percent to 32,987 as new entries such as the Nissan NV and Ram ProMaster added spice to a small and usually sleepy segment.
May was a get-well month for almost every brand. The seven largest automakers boosted sales, with Nissan North America, Chrysler Group, Toyota Motor Sales and General Motors up double digits.
May gains pulled American Honda and the Hyundai brand back to the plus side for the year to date. Even with a modest 3 percent monthly increase, Ford Motor trimmed its five-month volume losses to 1 percent.
"Everything came together," said Toyota Division General Manager Bill Fay, noting May had five weekends, an early Memorial Day and an extra selling day.
The only major player to lose in May was Volkswagen Group of America. The VW brand plunged 15 percent, overriding double-digit increases at Audi, Porsche and Bentley. But the group's net 3 percent decline in May was better than its 5 percent drop year to date.
May was the third straight month with selling rates above 16 million. That further eases fears raised by fierce winter storms that the sales recovery was faltering in its fifth year. Through five months, U.S. auto sales are up 5 percent.
"We're right back on track for a good year," said analyst Alec Gutierrez of Kelley Blue Book. He says he's again comfortable with his 2014 forecast of 16.3 million units. After May's rally Gutierrez sees more upside potential than down the rest of the year.
Larry Dominique, executive vice president of TrueCar, said consumers researching vehicles on TrueCar's Web site hit record levels the week after Memorial Day.
"Only some of those would show up in May sales" and most wouldn't until June or later, he said. "It seems like the ship is steady."
Auto executives are also looking ahead.
"Car sales are heating up as we head into summer," said Nissan sales boss Fred Diaz.
Honda Division General Manager Jeff Conrad said, "Our dealers are preparing for heavy customer traffic in the coming months."
Toyota's Fay cautioned against "some payback" in June sales, but thinks the industry will stay on a roll.
"We expect the overall momentum will continue, with near-record low financing options and a rebound in consumer confidence," he said. "There is every sign that the market stability we've seen for the last three months will continue through the summer."