FIA issue official weather alert at US Grand Prix

The temperatures at the 2025 US Grand Prix have been declared a heat hazard

Sheona Mountford F1 Journalist

Motorsport journalist working in F1 since 2024.

Friday 17 October 2025 18:57 Updated: 20:18

F1’s governing body, the FIA, have issued an official weather alert ahead of this weekend's United States Grand Prix and have declared the event a heat hazard.

Following the extreme temperatures and humidity experienced at the 2023 Qatar GP, the FIA began to analyse how similar conditions could be handled at future events.

Ahead of the 2025 season, the FIA announced their solution that if a weekend weather forecast predicts temperatures of 31 degrees Celsius or above during the sprint or a grand prix, a heat hazard will be declared.

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Last time out at the Singapore GP, the FIA declared F1’s first official heat hazard as the typically hot and humid climate at Marina Bay offered temperatures in the excess of 31 degrees Celsius.

Once again as F1 returns to Texas for the US GP, the FIA have confirmed that the race meets the requirements to be deemed a heat hazard.

Race director Rui Marques wrote: “In accordance with Article 26.19 of the Sporting Regulations, having received a forecast from the Official Weather Service predicting that the Heat Index will be greater than 31 degrees Celsius at some time during the Sprint or Race at this event, a Heat Hazard is declared.”

What does a heat hazard mean for F1 teams and drivers?

When a heat hazard is declared, teams need to fit a ‘driver cooling system’ which includes a pump, plumbing and thermal store. The cold fluid generated by the system is then delivered to the drivers through a fireproof vest which is composed of several tubes.

While all of these core system components must be fitted during a heat hazard weekend, drivers can choose whether or not to wear the vest.

The cooling vest has split the F1 grid, with the likes of George Russell and Carlos Sainz electing to wear the vest in Singapore, while Max Verstappen and Lewis Hamilton have been vocal opponents of the system.

If a driver chooses not to wear the cooling vest, 0.5kg of ballast must be fitted in their car's cockpit to avoid competitors abandoning the vest to gain a sporting advantage by running with less weight.

The FIA have stressed that they are open to discussion with drivers on how to improve cooling vests, as they consider making them mandatory for 2026.

Verstappen believes that cooling vests should remain a choice, while Russell welcomed the method when there is ‘90 per cent humidity’ and the inside of a cockpit feels like a ‘sauna’.

Williams star Sainz was happy to not make cooling vests mandatory, but also claimed that drivers who don’t want to use it will have a ‘disadvantage in the race'.

For updates across the United States GP weekend, you can find the full weather forecast from Friday to Sunday here.

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FIA United States Grand Prix