Around 270,000 spectators are expected at the Berkshire track over the five days.
Ascot is confident it can cope with a week of warm weather, with temperatures expected to reach as high as 29C by Saturday.
“Thoroughbred racehorses are able to run in very hot temperatures, including in countries such as Dubai,” said a course spokesperson.
“To ensure their welfare here at Royal Ascot we provide them with lots of water and ice if necessary.
“We’ve had days at Royal Ascot over 30C and we have a dedicated team of people to help cool the horses after they’ve raced.”
Going conditions are described as good to to firm, with the ground watered to help with safety for runners and riders.
The course’s dress code was relaxed for the first time during a heatwave three years ago, but the same is not expected to happen this week.