auto racingThis weekend's Singapore Grand Prix was on Thursday declared an official Formula One "Heat Hazard" -- the first time a new rule to help drivers stay cool has been invoked. "Having received a forecast from the official Weather Service predicting that the Heat Index will be greater than 31C at some time during the race... a Heat Hazard is declared," Marques said. Drivers can shed up to three kilograms during the night race that often lasts the maximum two hours race limit. The cooling vest system was developed after the 2023 Qatar Grand Prix, where several drivers needed medical attention after suffering in the heat. George Russell trialed the cooling vest at this year's Bahrain Grand Prix and gave it the thumbs-up.