Singapore GP declared ‘heat hazard’ F1 race: What does it mean and what happens next?

Formula 1’s governing body the FIA has declared this weekend’s Singapore Grand Prix a ‘heat hazard’ race, the fourth time the declaration has been used this year. 

The ruling comes into effect when temperatures are predicted to exceed 31 degrees during the event, triggering a heat index which the FIA uses to define potentially dangerous conditions for drivers. 

Weather forecasts suggest a hot weekend in Singapore, with temperatures likely to reach 33 degrees at points during the weekend. 

Singapore is the sixth F1 race to be designated a ‘heat hazard’, following the Singapore and United States Grands Prix last year, and this year's Austrian, Italian and Bahrain grands prix. 

The safety regulation gives drivers the option of wearing cooling vests to help combat extreme temperatures. 

F1’s rules also state that the minimum weight of the car is increased by five kilograms to accommodate the hardware used to run the liquid-cooled vests worn by drivers. 

Drivers can decide not to wear cooling vests, but those who opt out will have to run with extra ballast to compensate, ensuring they do not gain a competitive advantage. 

How do the vests work? 

The cooling vests feature a liquid such as glycol pumped through a tank of dry ice and through the driver’s fireproof top. 

However, there are some drawbacks, such as driver comfort and the possibility of dry ice running out, which would lead to the liquid being pumped through the system at car temperature. 

George Russell, a director of the Grand Prix Drivers’ Association (GPDA), has praised the solution, which he wore on his way to winning in Singapore last year. 

"Not everybody finds the top comfortable, but I think some find it more comfortable than others, and of course over time you'll be able to adjust it to your own preferences," the Mercedes driver said. 

"But the concept is good, and when you're racing in 90% humidity and the cockpits are getting on for 60C, it's a bit of a sauna inside the car, so I think we all welcome it.”

Not every driver likes them, with Max Verstappen describing the vests as uncomfortable and problematic.

Why was the rule introduced? 

The rule was brought in last year in response to extreme conditions at the 2023 Qatar Grand Prix, which left several drivers on the brink of collapsing and requiring medical attention. 

Esteban Ocon threw up in his helmet, while Logan Sargeant retired because he could not cope with the conditions inside the cockpit of his Williams car. 

In a newly-announced rule tweak for 2026, the ’heat hazard’ declaration can now be enforced between a sprint and main race, if required. 

"The declaration of a Heat Hazard may now be split between Sprint and Race. A Heat Hazard will still be declared, for Sprint, Race or both, 24 hours prior to the start of the Competition,” the FIA states.