SARATOGA SPRINGS — The six-week whirlwind of magic on Union Avenue starts today.

But don’t expect Saratoga’s crown jewel to start shining right away. Rain is expected throughout the afternoon today and into Thursday morning, which may limit crowds at Saratoga Race Course to the most diehard racing fans.

Rain is expected to start late this morning and continue until Thursday morning, up to 2 inches total, said Brian Frugis, meteorologist with the National Weather Service in Albany. “The rain is going to be falling heavily at times,” he said.

On Thursday, the sky will clear up, and Friday is expected to dawn clear and partly sunny with highs in the mid-80s, Frugis said, setting a good stage for the meet’s first Sunset Racing day, when post time is at 2:45 p.m., and the Hats Off to Saratoga Festival that starts Friday evening downtown.

A chance of thunderstorms could mar the Breeder’s Cup Challenge Day on Saturday, when highs are expected to reach the lower 80s, Frugis said.

The weather is expected to be pretty unpredictable most of the week, he said: “It’s going to be pretty unsettled.”

Sunday’s weather may be a little more conducive to outdoor activities, with no rain or storms in the forecast.

Regardless of the weather, workers in and around the track will be ready when the first post time arrives at 1 p.m. today.

Lizzie Schlegel spent Tuesday overseeing other teens training to use the cotton candy and popcorn machines at the P&H Popcorn stand. She said she arranges her whole summer around working at the track.

“I kind of like the atmosphere,” the 17-year-old Stillwater teen said. “It’s always crazy busy. I can’t think of doing anything else.”

New this year at the track is “Saratoga Restaurant Row,” a sampling near the clubhouse entrance of the best eats for $4 to $7 from five local restaurants — Hattie’s on Phila Street, Brindisi’s on Broadway, Grey Gelding on Broadway, Panza’s on Saratoga Lake and One Caroline Street Bistro/Mouzon House.

Air conditioning has been installed in the newly-enclosed At the Rail Pavilion and Paddock Tent, as well as a special hospitality lounge at the finish line.

Some other dining areas will have a slightly relaxed dress code from years past, with shorts allowed in the At the Rail Pavilion, The Porch, Club Terrace and Carousel Restaurant.

Proper attire is still at the management’s discretion in those areas, which don’t allow short shorts or cut-offs on men or women or tank tops for men.

Businesses outside the track were getting ready on Tuesday for the start of the season, too.

Ashley Hotaling stacked Saratoga souvenir T-shirts in the seasonal stand on Union Avenue run by the Saratoga Army & Navy Outfitter store on Broadway.

“This is my first time doing this, so I’m pretty excited,” said Hotaling, 19, of Ballston Spa.

And she’s not even a racing buff: “I travel by it a lot and see it on TV and stuff.”

But for most other people setting up at the track on Tuesday, horse racing is a way of life.

Agents lined up to draw post position for their jockeys for a Thursday race, a random part of a competitive business.

“We’re friends, but business is business,” said agent Tony Micallef, who draws for jockey Alan Garcia, as the agents kidded with each other while they waited.

Around the racing grounds, workers set up food stands, dusted mutuel bay windows and made sure electronic betting machines were working properly.

Trunks shipped from Belmont Park waited alongside the walkways to be unpacked.

All the work made for a busy day before a busy six weeks, but things were going better than they did over the weekend at Belmont, where the last day of racing Sunday was cancelled because a transformer fire Saturday blew the whole operation’s air conditioning system, messing up the dining rooms, kitchen and computer rooms, said New York Racing Association spokesman John Lee.

“The jockeys’ room in the basement was like a sauna,” Lee said.

The drama complicated the move, which happens in three installments, he said — last Wednesday, Saturday and Sunday.

Near the winner’s circle, Mark Jennings of Albany was getting ready for six weeks of working at the coolest job at the track.

Jennings will be the bartender at the Saratoga Preferred Access lounge, a new air-conditioned area with a view of the finish line that people can reserve for between $150 and $500 per person per day.

“I definitely landed in a good spot,” Jennings said of the air conditioning.

The lounge, which has a private bar and table seating, is geared toward businesses that want to entertain clients, said Jim Rossi, managing partner of the Saratoga Polo Association, which provides staff and management for the VIP program.

“The track has been a difficult place for business entertaining,” Rossi said.

About a dozen people bought spots in the lounge for the entire season, and 45 people total can enjoy the facility each day, he said.

Although the hospitality suite is new, this is the VIP program’s second year, Rossi said. “It was a successful program last year when we did it sort of as a test,” he said. For reservations, call Jim Shelffo at 429-5772.

Just down Union Avenue, the National Museum of Racing and Hall of Fame is ready for its busiest season as well, said spokesman Mike Kane. Its exhibit “Ride on!” about equine veterinary medicine opened Sunday.

At least 85 percent of the museum’s 35,000 guests come through during the summer season, Kane said.

“Our whole business just comes to life with the racing season,” he said.

Mornings are especially busy, before the track opens, Kane said. “If you want to take a leisurely stroll in the museum, come in the afternoon.”

The museum also is showing “First Saturday in May,” a documentary about the 2006 Kentucky Derby, 40 times during the racing season.