Overview

• Race director Rui Marques declared the event after forecasts showed the Heat Index exceeding the 31°C threshold, with the designation applying for the remainder of the weekend.
• Teams must install the full driver cooling system on their cars, and any driver who opts not to wear the vest must carry 0.5kg of ballast in the cockpit.
• The system pumps cooled liquid through tubing in a fireproof vest and relies on onboard hardware including a pump, reservoir or thermal store, and a heat exchanger.
• Drivers report mixed results from trials in 2025: George Russell cited clear cooling benefits, while others flagged discomfort and reliability concerns, with failures potentially making the cockpit feel hotter.
• News outlets report the cooling vests are set to become mandatory in hot conditions from next season.