The FIA has declared a heat hazard for both the Singapore Sprint and Grand Prix, forcing every team to carry driver cooling systems. Mercedes has decided George Russell and Kimi Antonelli will not wear a vest, taking the ballast route instead.
Singapore: The declaration came on Thursday, before any running at Marina Bay, after the official weather service forecast that the heat index would exceed 31 degrees Celsius at some point during the Sprint or the Grand Prix. That forecast is the trigger under Article B1.5.10 of the FIA regulations, and it puts a cooling requirement on the whole field before a wheel has turned.
What the Hazard Demands
Every car must now carry the approved driver cooling system for the relevant sessions. The kit pumps cooled fluid through tubing in a fireproof garment worn beneath the race suit, and it was introduced after the 2023 Qatar Grand Prix, where several drivers needed medical attention. Wearing the vest is a choice. A driver who goes without must carry 0.5kg of compensating ballast in the cockpit, so that nobody is penalised for the decision.
Why Marina Bay
Singapore is a night race, but darkness does little for the drivers. Humidity typically sits between 70 and 90 per cent, the street circuit offers limited airflow and the race is long, which is why this event is the most obvious candidate for a declaration even after sunset.
Mercedes Goes Without
Mercedes will take the ballast option, as it did at earlier heat-hazard rounds this season. The team concluded that running its own cooling system reliably across a full race distance was not viable and would divert resources from car development, so neither Antonelli nor Russell will wear a vest on Sunday.
It adds another demanding layer to a weekend that already looks hard for Russell. He retired from third place in the rain-hit race at Sepang that Max Verstappen won, and Mercedes has said he will take an engine penalty that sends him to the back of the grid for the Grand Prix, though not the Sprint. Antonelli leads him by 84 points with seven rounds left.
What Comes Next
The Sprint is on Saturday and the Grand Prix follows on Sunday at 8pm local time. With a heat hazard in force for both, cooling will be part of the strategy conversation as much as tyres and engines.
