But this year might lack some colour as thousands of tickets remain unsold.
Historically, the second day of the meeting has sold out well in advance, but last year organisers failed to sell between 3,000 and 4,000 tickets.
This year about double that amount – 7,000 – remained unsold yesterday, ahead of Ladies Day today.
Organisers said they were "puzzled" by the lack of demand, but suggested the cost of dressing up could be to blame.
One Liverpool-based fashion boutique indicated that some regular attendees might have been put off by photographs of 'ladettes' – women engaging in lewd behaviour and wearing risqué clothing at the event.
"I think people felt that they didn't want to be a part of that, so maybe they chose to go on a different day," said Justine Williams, the managing director of Cricket, whose clients include Coleen Rooney, wife of footballer Wayne Rooney.
"Thursday has become a lot more popular, and Saturday as well. We have seen a real shift," she said.
Nigel Payne, an Aintree spokesman, said: "It's historically a great day for the locals (but) I think money is a lot tighter than it was.
"It has puzzled us. We expected it to have sold out very early on. Two years ago we sold out well in advance, last year we didn't quite sell out and now we have got this.
"It has picked up a bit in the last week but not as much as we expected."
He added: "We are still going to have a very healthy crowd of well over 40,000."
The cost of tickets increased this year, but only marginally, Mr Payne said. Prices range from £37 (€45) to £179 (€217).
Mild weather and sunny spells are forecast for the racecourse today, which organisers hope will prompt more sales.
Tickets for tomorrow's Grand National Day have sold out.
Favourites for the race include Monbeg Dude, part-owned by rugby's Mike Tindall. His wife Zara Phillips famously branded him an "idiot" for buying a share in the horse.