FIA declares Heat Hazard for Sepang: what it means for F1 drivers this weekend

The FIA has officially declared a Heat Hazard for this weekend's Gulf Air Bahrain Grand Prix at Sepang International Circuit. Teams now have to prepare for one of the hardest physical races on the 2026 calendar.

FIA race director Rui Marques made the declaration on 30 September under the Formula 1 regulations, after the official weather service forecast a heat index above 31.0°C during the race.

What the FIA said

The notice was short. "Having received a forecast from the Official Weather Service predicting that the Heat Index will be greater than 31.0°C at some time during the Race at this Competition, a Heat Hazard is declared," the FIA stated, as reported by GPBlog.

The heat index combines air temperature and humidity to measure how hot conditions feel. Malaysians know the feeling well, and on Sepang's wide, exposed tarmac it is even more intense.

What changes for teams and drivers

Motorsport Week reports that a Heat Hazard requires teams to fit Driver Cooling System components to their cars. Drivers can choose whether to race with a specialised cooling vest. If they don't, teams must add ballast so that no car gains a weight advantage.

Not every driver is convinced by the vests. Max Verstappen and Lewis Hamilton are among the drivers who have questioned how effective they are over a full race distance.

According to Motorsport Week, Sepang is the third Heat Hazard declaration of the 2026 season, after Austria and Italy.

The forecast

GPBlog published the official forecast behind the decision:

• Friday, 2 October: maximum 32°C, 80% humidity, 50% chance of rain
• Saturday, 3 October: maximum 32°C, 70% humidity, 40% chance of rain
• Sunday, 4 October (race day): maximum 31°C, 70% humidity, 30% chance of rain

Rain is still possible every day, so teams will be planning for heat and wet weather at the same time. Sepang has a history of sudden downpours. In 2009, the race was red-flagged because of heavy rain and never restarted.

Why Sepang is so physically demanding

Sepang combines long straights, fast corners and heavy braking zones with tropical heat and humidity. Fernando Alonso has compared the conditions to Singapore, except that the Malaysian race takes place in daylight. Hamilton described F1 as "supposed to be the sport that's the most physically demanding, mentally and physically".

Twelve drivers on the grid have never raced here, so many are working out how their bodies cope with the conditions as well as learning the layout. Several have arrived early to acclimatise. Cadillac's Valtteri Bottas, for example, has been cycling near the circuit.

Advice for fans

Spectators will also feel the heat. Grandstand and hillstand ticket holders should drink plenty of water, wear sun protection and bring rain gear, because conditions at Sepang can change from scorching to stormy within an hour. Practice starts on Friday, and the race begins at 3pm on Sunday.

Key takeaways

• FIA race director Rui Marques declared a Heat Hazard for Sepang on 30 September.
• The trigger is a forecast heat index above 31.0°C during the race.
• Teams must fit Driver Cooling System parts, and drivers can choose to wear cooling vests.
• The forecast shows highs of 31–32°C with a 30–50% chance of rain each day.

FAQ

What is an FIA Heat Hazard? It is a declaration made when the heat index is forecast to exceed 31.0°C during a race. It requires cooling equipment to be fitted to the cars.

Do drivers have to wear cooling vests? No. Wearing the vest is optional, but teams must add ballast if a driver races without it.

Will it rain during the Sepang race? The official forecast gives a 30% chance of rain on Sunday, so a wet race can't be ruled out.

Sources: GPBlog, Motorsport Week, Formula1.com, Sky Sports, SAYS