Lewis Hamilton says the tropical conditions at the Malaysian Grand Prix make it the toughest race of the year.
The Englishman, who won the first F1 race of the season in Australia last weekend, expects the humidity at Sepang to test all the drivers on Sunday.
"It was the hardest race I have ever competed in last season," Hamilton said. "You cannot begin to imagine how hot it gets in the car.
"The climate plays a major role in making it very tricky for all of us."
Hamilton finished second behind Fernando Alonso in Malaysia last season - how do you think he will fare on Sunday?