The Singapore Grand Prix has officially become the first Formula 1 race to be declared a “heat hazard” under new FIA regulations, as soaring temperatures and extreme humidity are expected to push drivers to their physical limits this weekend.
The ruling, introduced this year, comes as forecasts predict conditions exceeding 31C with around 90% humidity in the tropical city-state. While the use of cooling vests is not mandatory, the FIA has instructed teams to fit their cars with the system to prevent any competitive imbalance, ensuring that drivers who opt out are not rewarded with a lighter car.
Although this will be the first time the FIA has designated a race under the heat hazard rule, cooling vests have already been trialed intermittently throughout the season. Mercedes driver George Russell, a director of the Grand Prix Drivers’ Association (GPDA), tested the system in Bahrain and welcomed its introduction in Singapore.
“Not everybody finds the top comfortable, but I think some find it more comfortable than others,” Russell said. “When you’re racing in 90% humidity and the cockpits are reaching 60C, it’s a bit of a sauna inside the car. I think we all welcome it.”
Ferrari’s Carlos Sainz, also a GPDA director, backed the FIA’s decision, calling it “fair.” He explained that Singapore’s unique combination of heat and humidity makes it one of the most physically punishing events on the calendar. “Only hot is not too bad for us,” Sainz said. “But when it’s 30C plus and humid, that’s when it gets to Singapore levels and it’s tough.”
The Marina Bay circuit is already notorious among drivers for its challenging conditions. The race often runs close to the maximum two-hour limit and features a bumpy track surface that adds to the physical strain.
The FIA’s new heat hazard rules were introduced after the 2023 Qatar Grand Prix, when extreme conditions left multiple drivers needing medical attention. Williams driver Logan Sargeant was forced to retire, while Alpine’s Esteban Ocon admitted to vomiting in his helmet mid-race.
Since then, teams have worked to improve the vest system, though its effectiveness has been mixed. Sainz revealed that earlier prototypes lasted just half an hour, but recent iterations are edging closer to lasting an hour. “It’s a two-hour race,” he said. “If it works, you suffer less. If it doesn’t, I’ll still finish fresh, like always.”
Aston Martin’s Fernando Alonso echoed that the system “works,” but admitted the trade-off in comfort can be frustrating. “The shirt is thicker with the tubes inside, so it is less comfortable. It is a trade-off—it cools you, but it’s not comfy,” he said.
The technology works by circulating cooled liquid through a tube embedded in a fireproof vest worn under the drivers’ suits. But if the system fails mid-race, the vest itself becomes an insulator, trapping heat and potentially worsening conditions for the driver.
Teams have taken different approaches to integrating the cooling system. Some have installed the pumps at the front of the chassis, others near the side-impact structures, and some inside the car body itself. Each solution has presented its own engineering challenges.
Russell admitted the design is not flawless, noting that the tubes press against his ribs in high-speed corners under heavy G-forces. “They’ve improved it, but it’s still not perfect,” he said. “Luckily, in Singapore there aren’t many high-speed corners with big lateral loads, so I don’t think it’ll be a major issue.”
Despite the trade-offs, the consensus among drivers is that the FIA’s move is a step in the right direction to protect athletes from the extreme demands of modern Formula 1. As the night race in Singapore approaches, all eyes will be on how the cooling system performs in one of the sport’s most grueling tests of endurance.
