Summer's over. The roar of the roller coaster has grown silent. Regional amusement parks have locked their turnstiles and sent all but a skeleton maintenance crew home. But like a glass house of mirrors, all is not how it appears to be. Yes, most of the thrill parks have shut down for the season, but this is the industry's biggest week.

Why? Cedar Fair(NYSE: FUN) and Six Flags(NYSE: PKS) posted third-quarter results. The country's two largest regional amusement park operators live and die by this quarter, earning more during the summer period than they do all year. They have historically reported a loss through the other three quarters, only to turn it around with gusto in July, August, and September.

Cedar Fair reported earnings of $2.01 a diluted share, two pennies ahead of Wall Street's projections. But that was almost a given. It has been the picture of consistency, even bucking industry trends while operators like Disney(NYSE: DIS) and Six Flags have warned of dramatic drop-offs in attendance.

Through the first three quarters, Cedar Fair actually reported a 3% attendance gain. You haven't heard that kind of feel-good news from Disney or Universal Studios park operator Vivendi(NYSE: V), and you won't hear it from Six Flags, either, when it reports tomorrow.

While Six Flags has hinted it's beginning to bounce back from an early summer lull, investors aren't lining up for the ride. The stock has surrendered more than two-thirds of its value this year, as the leveraged company has provided more ups and downs recently than its collection of scream machines.

Last month, Six Flags announced that, after a soft June and July, business picked up and stayed up through the summer's end. Analysts expect the company to report earnings of $1.45 a share tomorrow, but it will be even more interesting to hear what it has to say during its Thursday morning conference call. Will Six Flags sell off some assets? Will it invest in needed park improvements? Either extreme might be welcome right now, because staying the course landed the stock at the bottom of the lift hill.

Sure, summer's over, but for amusement park operators, next summer starts now. Fasten your seat belts. The ride's not over yet.