Western Europe, which traditionally enjoys moderate summertime temperatures, has experienced extreme heat over the past weeks. On Day 2 of the dressage Grand Prix at the Chateau de Versailles venue (July 31), the temperatures hit 96 F with a side helping of humidity, yet the horses and riders sailed through, and by all accounts the individuals who suffered the most were the spectators, broiling on unshaded metal bleachers.  

Weather Monitoring at The Olympics 

The weather-watching in Paris 2024 and other major FEI events consists of much more than glancing at a weather app and checking radar for storm activity (although sophisticated radar systems and weather experts do play a part, as in Tokyo 2021, when officials halted competition several times to allow thunderstorms to pass), said Göran Åkerström, DVM, veterinary director for the Fédération Equestre Internationale (FEI).  

This summer Åkerström is the lead monitor of a sophisticated heat index called the wet bulb globe temperature (WBGT) for Olympic equestrian sport. This is much more complex than the heat and humidity index your local meteorologist uses to calculate the “real feel” temperature when you walk out the door. Experts calculate the WBGT—a measure of heat stress in direct sunlight—using not only air temperature and humidity but also wind speed, sun angle, and cloud cover (solar radiation). 

When the forecast predicts a WBGT over 82 F, Åkerström alerts both the ground jury and competition management to activate the FEI’s heat-monitoring and -mitigation systems and protocols. These include having trained veterinarians use special thermographic cameras to monitor horses’ surface temperatures before, during, and after competition; providing cooling stations in the warm-up arena and just outside the competition arena containing ice water and fans; and stationing a misting tent with fans near the arena, where grooms can take horses for additional cooling before they return to the stables.   

As for the thermographic cameras, “You need to be over 25, 26 WBGT, otherwise it will not be functional, that monitoring method; but above that it works really well,” Åkerström said. “The correlation between the true body temperature and the readings from a certain distance on a certain part of the horse correlates extremely well with the rectal temperature.” 

Monitoring exercising horses at the Olympics is “an active process of assessment,” said Emily Sandler-Burtness, DVM, Paris 2024 FEI foreign veterinary delegate, FEI Level 4 veterinarian, of Coast Equine Veterinary Services in Ramona, California. It’s more than just taking readings with a camera. “(It’s) correlating how they look clinically with their surface temperature, with the WBGT,” she said.  

How Do Olympic Horses Handle the Heat? 

Horses tend to handle heat better than humans, said Åkerström, who notes that the WBGT hit 33 in the competition arena on July 31, which ended up being the hottest day of the 2024 Olympic equestrian competition. “The horses actually looked really good,” Sandler-Burtness said.  

Sandler-Burtness and the rest of the Paris 2024 veterinary team were thankful, she said, that eventing cross-country day (July 28) didn’t happen to land on that 96-degree day—although if it had, they would have been ready. Cross-country day in Tokyo 2021 was around 34 WBGT, says Åkerström, yet thanks to massive preparatory and mitigation efforts, there were “no issues whatsoever with heat, with horse welfare, with one single horse.” 

There is no defined WBGT threshold at which competition is canceled, Åkerström said. That’s because he and his team must consider the degree to which the horses have been prepared for the conditions. Tokyo 2021 went as smoothly as it did in part because everyone expected it to be very hot, he explained, and they prepared and conditioned their horses accordingly. An unanticipated hurricane and heat wave, such as the ones during the 2018 World Equestrian Games in Tryon, North Carolina, might be another story, and the FEI could have to make changes quickly. 

Climate and the Future of Equestrian Sports  

“(The FEI is) much aware that we are moving toward a warmer climate, a more unpredictable climate,” said Åkerström. The FEI is in ongoing discussion with the International Olympic Committee (IOC) on the topic, as well, because equestrian sports aren’t the only ones affected. The weather extremes also greatly impact sports such as the marathon and triathlon, he pointed out.  

The FEI has the power to set the dates for its own championships—it pushed back Tryon 2018, for instance, three weeks from August to September because historic weather data showed September to be cooler (the ensuing heat wave and hurricane were so severe Åkerström canceled the remainder of the endurance event). However, the IOC sets the Olympic dates. There have yet been no major shifts in the dates of Summer Games. Instead, sports likely to be adversely affected by heat might be moved to cooler locales, Åkerström said.  

Sometimes time-of-day scheduling can allow equestrians to compete in cooler temperatures. In Beijing 2008 most of the equestrian competition, which was held in Hong Kong, took place in the evening, and cross-country started early in the morning. Mother Nature might be growing more volatile, but scientists are working to ensure the safest possible conditions for equine Olympic athletes.