Europe is sweltering. How will the Tour de France deal with extreme heat?

Temperatures are climbing across the continent, placing pressure on public services, agriculture, transport and major outdoor events. In parts of southern Europe, daytime temperatures are approaching 40°C, while warm nights offer little opportunity for the body to recover.

For the peloton, those conditions are already more than a distant concern. Riders at the Tour de Suisse last week competed in temperatures well above 30°C, offering an early indication of what a summer of extreme heat could mean for them.

“It was pretty hot,” Tadej Pogačar said after the first stage. “After the descents, it felt like someone was blowing a hairdryer into your face.”

But air temperature alone does not determine the level of risk during a cycling race.

Humidity affects how easily sweat can evaporate. Direct sunlight increases the amount of heat absorbed by the body. Wind and rider speed influence cooling. Clothing, race intensity, heat acclimatisation and the availability of fluids also play a role.

For that reason, the UCI uses the Wet Bulb Globe Temperature index, commonly known as WBGT, to assess heat stress during road races. Although the index is expressed in degrees Celsius, it is not the same as the forecast air temperature.

WBGT combines air temperature, humidity, solar radiation and wind into a single measure of environmental heat stress. For cycling, the estimated speed of the peloton can also be included to account for the cooling effect of the airflow riders experience while moving.

The UCI introduced its dedicated High Temperature Protocol in early 2024. It complements the broader Extreme Weather Protocol, which has been in place since 2015.

The protocol was developed to create a more objective system for assessing heat related risk and to identify measures that can protect riders, teams, officials, volunteers and other people working at an event.

When dangerous conditions are expected, a meeting can be convened involving the president of the commissaires’ panel, the race director, the race doctor, the head of safety, team representatives, a riders’ representative and, when present, a UCI representative.

The group reviews the available weather information, estimates the WBGT level and considers the characteristics of the race. It can then recommend measures based on five risk categories.

The categories do not function as automatic instructions. A red classification does not necessarily mean that a race will be cancelled, just as an orange classification does not guarantee that it will continue unchanged.

The protocol provides a framework for discussion. Organisers and officials must still consider the route, the expected race speed, the time of day, the availability of shade, the location of medical services and the possibility of modifying the event safely.

In the green zone, the recommendations mainly focus on preparation. Riders can warm up in the shade, use fans, wear light coloured clothing and follow their normal hydration strategies.

The yellow zone brings more active cooling measures. Teams can use ice vests, cold towels and ice socks before or during the race. Riders are expected to follow individual hydration plans, while organisers may need to ensure that more ice is available.

In the orange zone, the organisation can take additional operational measures. Riders may be kept in shaded areas before the start. Extra support can be provided for officials and volunteers. Neutral motorbikes carrying drinks and ice may be added to the race convoy, while regulations concerning access to bottles and cooling can be adjusted.

The red zone allows for the most significant interventions. The start or finish time can be changed, part of the race can be neutralised, or the stage can be shortened or cancelled.

Some of these measures may be highly visible, but many are not. Additional ice, shaded waiting areas, changes to the bottle supply and modified warm up routines can all be introduced without altering the format of the race.

Few races are as regularly exposed to extreme heat as the Vuelta a España. Held at the end of the European summer, the race has often sent riders through long stages in temperatures above 30°C.

That challenge could become even more prominent in 2026. The route focuses heavily on Spain’s eastern and southern regions, while largely avoiding the cooler north, raising fresh concerns about the conditions riders may face.

Speaking recently, race director Javier Guillén said heat could not dictate where the race is held. “The heat cannot prevent us from going to certain areas,” he said. “It is part of the competition and we must adapt to these conditions.”

Guillén added that protocols are in place for extreme temperatures and that each situation will be assessed as it arises. 

But as European summers continue to grow hotter, the UCI’s High Temperature Protocol, introduced in 2024, may soon face calls for further revision.