SINGAPORE - Red Bull's Max Verstappen has called the Singapore Grand Prix the 'toughest race for the whole season', pointing to the Republic's humidity and the Marina Bay Circuit's multitude of corners.

"In my country, you don't sweat just from walking around, but here you do," said the Dutchman on Wednesday (Sept 13), when he made a series of event appearances after arriving in Singapore the day before.

"The last few months, I've done some heat training and also just sitting in the sauna to get used to the sweating."

Verstappen, the youngest driver to have won a Formula One Grand Prix, added that the Marina Bay Circuit's many corners present a stiff challenge to drivers.

"You have to be really precise and cannot make too many mistakes because if you miss one (corner), you also miss the next," he said.

The 19-year-old got a full preview of the heat he will face in the car come Sunday (Sept 17) on a sweltering afternoon at Wisma Atria, where he made an appearance for team sponsors Tag Heuer.

There, he interacted with guests and Tag Heuer ambassador Patrick Dempsey of American TV series "Grey's Anatomy" fame.

Verstappen comes to Singapore lying sixth (68 points) in the drivers' standings, having endured a wretched first half of the season that saw him fail to finish six races.

He said: "It's definitely not gone my way this year, but you just try to learn from the situation and try to improve what you can."