Singapore, Sep 14 (IANS): Force India driver Nico Hulkenberg feels the Singapore Grand Prix in the toughest race of the Formula 1 calendar because of the heat, despite being held at night.

"The Singapore Grand Prix ranks as the toughest race of the year because of the heat. It's physically draining and you've also got the mental challenge of racing so close to the walls with a small margin of error. We go there knowing we've made some good steps with the car over the last few races and aiming for more good points," Hulkenberg said on Monday.

The weekend will see Formula 1 cars take to the Marina Bay Street Circuit for the 13th round of the season. The Singapore GP was the first and still one of the few night races in the F1 calendar.

"I've always enjoyed racing in Singapore and it's one of the best events of the year. The city is buzzing and there's a great atmosphere wherever you go," said the German.

"When it's all lit up at night it looks stunning. I often wonder how much work is required to transform such a busy city into a racetrack. It's clearly a huge logistical operation, but it's definitely worth all the effort."

Four-time World Champion Sebastian Vettel is the most successful driver on the 5 km circuit, winning the 61-lap floodlight lit race thrice, one more than both Fernando Alonso and Lewis Hamilton.

"The track layout has some nice features, but the first sector stands out for me - especially the fast right-hand kink of turn six and the braking zone of turn seven. You need a car that's able to ride the bumps, can use the kerbs and gives you confidence through the low and medium-speed corners," said Hulkenberg.