Formula One has declared a heat hazard for this weekend’s Italian Grand Prix at Monza, requiring teams to prepare additional cooling equipment for drivers as temperatures are forecast to climb above 31 degrees Celsius (88 degrees Fahrenheit).
Race Director Rui Marques announced the designation after the official weather forecast predicted a heat index exceeding 31 degrees Celsius during Sunday’s race. It is the second time this season the FIA has activated its heat-hazard protocol, following the Austrian Grand Prix in June.
Temperatures around Monza, northeast of Milan, are expected to reach the mid-30s Celsius during the weekend, with forecasts calling for highs of about 33 to 35 degrees Celsius on race day. Temperatures near Milan’s Linate airport reached 36 degrees Celsius earlier in the week.
The conditions could make an already demanding race even more difficult for drivers. Cockpit temperatures can rise well above the outside temperature because of heat generated by the power unit, restricted airflow and the multiple layers of fireproof clothing drivers wear.
What the heat hazard means
The FIA introduced the heat-hazard protocol for the 2025 season after extreme conditions at previous races, most notably the 2023 Qatar Grand Prix, where heat and humidity placed severe physical strain on drivers.
Under Article B1.5.10 of the FIA Formula One Sporting Regulations, a heat hazard can be declared when the official forecast predicts a heat index above 31 degrees Celsius during a Sprint or Grand Prix. The Race Director also has discretion to activate the protocol.
Once declared, teams must install a Driver Cooling System in their cars for the affected session.
The system uses a pump, plumbing, a thermal store and refrigerant fluid to circulate cooled liquid through tubes incorporated into a specially designed fireproof vest worn beneath the driver’s overalls. The equipment is intended to provide additional cooling and reduce the risk of heat-related problems during the race.
Drivers are not required to wear the cooling vest. However, those who choose not to use it must still carry the required system hardware and cooling medium. They must also add 0.5 kilograms of ballast to the cockpit to account for the difference in weight, preventing drivers from gaining a competitive advantage by opting out of the vest.
The system itself adds roughly 5 kilograms to the car’s minimum weight.
The cooling technology remains a work in progress. Some drivers have previously complained about discomfort caused by the tubing, while others have reported that the coolant can lose effectiveness before the end of a race.
The protocol was also used at the 2025 Singapore and United States Grands Prix, while the Austrian Grand Prix became the first event of the 2026 season to receive the designation. Recent regulatory changes allow the FIA to apply the heat-hazard protocol separately to a Sprint and the main Grand Prix if conditions warrant.
Antonelli's home run
The heat will provide an additional challenge for Kimi Antonelli, who arrives at his home race as the championship leader.
The 20-year-old Mercedes driver leads the standings after 12 rounds with 242 points, 59 ahead of Mercedes teammate George Russell and Ferrari’s Lewis Hamilton, who are tied on 183. McLaren’s Lando Norris and Ferrari’s Charles Leclerc are also among the leading contenders.
Mercedes leads the constructors’ championship.
Antonelli, who has scored multiple victories and pole positions this season, will nevertheless face a major obstacle at Monza. Mercedes is installing a new power unit after he exceeded his allocation of certain power-unit components, meaning he is set to start from the back of the grid.
Mercedes team principal Toto Wolff has described the decision as a calculated championship move. Monza’s long straights and several overtaking opportunities make it a more favorable circuit for recovering positions than many other tracks.
Antonelli has said he will attack the race aggressively, knowing he has little to lose from the difficult starting position.
Monza is known as the "Temple of Speed” because of its long straights and exceptionally high average speeds. The circuit places significant demands on power units, brakes and cooling systems even under normal conditions.
This weekend, teams must also account for the added weight and packaging requirements of the mandatory driver-cooling equipment, while drivers will have to manage the physical effects of racing in unusually hot conditions.