See Triple Crown winner American Pharoah this summer in Del Mar

The Del Mar racetrack, formally known as the Del Mar Thoroughbred Club, will open its gates at the Del Mar Fairgrounds on Thursday for the summer season. As is the case at many horseracing events, hats matter.

The surf-meets-the-turf racetrack, about 100 miles southwest of Los Angeles, will host a rock star in the middle of its season. Triple Crown-winner American Pharoah, which made his debut on the San Diego area track last year, will train there (you can catch him at morning workouts) but isn’t expected to run.

For opening day, you can pay $10 to enter the racetrack but $30 gets you into the Party on Opening Day. Party people get access to private betting and shaded seating as well as DJ-driven music, gourmet food trucks and a beer garden and cocktail bar.

The club also will host an Opening Day Hats Contest in which visitors may sign up to enter for free, either online or in person.

Prizes will be awarded to those with the most glamorous hat, the one that portrays the best racing theme, the most outrageous or funniest, the best fascinators (those tiny, clip-on hats), and the best flowers and all others.

The grand prize winner, named for Bing Crosby who was a co-partner in the racetrack, wins a two-night stay in a suite at the hotel-casino Harrah’s Resort Southern California in nearby Valley Center. It also comes with a $200 meal credit and $200 spa credit at the resort.

And if you want some insider tips, Frank Scatoni, author of books on betting and horse racing, will hold court at a Newcomers’ Seminar one hour before the first race.

Del Mar remains open daily except Mondays and Tuesdays. The season ends Sept. 7, Labor Day, the only Monday it will be open.

The racetrack also will bring back its Bring Crosby Season this year from Oct. 29 to Nov. 29.

Info: Del Mar Thoroughbred Club, 2260 Jimmy Durante Blvd., Del Mar; (858) 755-1167