How the French Open Is Using Heat Monitoring to Keep Players Safe

The French Tennis Federation has put a new system in place at Roland Garros to measure dangerous heat levels and stop play when conditions get too risky. When the heat measurement reaches 32.2°C (90°F), matches are paused on outdoor courts. This is the first time the French Open has set a firm temperature limit to protect players.

The federation uses two heat-measuring devices on-site that check not just the air temperature, but also humidity, sunlight intensity, and wind. Think of it like the difference between looking at a thermometer indoors versus standing outside in direct sun — you feel much hotter outside because of all those factors working together. So far, no matches have been cancelled due to heat under this system.

How the Heat Management Works

The tournament uses a step-by-step approach. When the heat reading hits 30.1°C before a singles match starts, players can take a 10-minute break before a potential third set (for women) or fourth set (for men). This gives them time to cool down without stopping the match.

When the reading reaches 32.2°C, play stops completely on the open-air courts. However, the tournament's three main courts — Philippe Chatrier, Suzanne Lenglen, and Simonne Mathieu — have retractable roofs and air conditioning. So matches can continue inside those covered courts while outdoor play pauses. This lets the tournament keep some matches going while protecting players on exposed courts.

Understanding the Heat Measurement

The measurement the French Open uses is called WBGT (wet bulb globe temperature). It is more detailed than the simple heat index you might see in a weather forecast.

A basic heat index only looks at air temperature and humidity — useful for a general idea of how hot it feels. WBGT goes further. It measures the actual temperature of a wet thermometer (which reflects how much sweat can evaporate from your skin), a regular thermometer reading the air, and a special black sphere that captures the heat from direct sunlight. Together, these three readings show the real thermal stress an athlete faces in that specific location.

This matters for outdoor sports because sunlight and reflective surfaces can create pockets of intense heat that weather stations far away might not catch. On-site monitoring at the tennis venue is far more accurate for player safety than relying on readings from a distant weather office.

Different Courts, Different Heat

Research published in Nature Scientific Reports found that heat varies across different tennis surfaces. Clay courts — the surface used at Roland Garros — reached the highest heat readings, followed by sand-filled artificial grass, and then hard courts. The difference comes down to how each surface absorbs and holds heat.

Clay's particular properties mean it soaks up and radiates heat more than other surfaces. That is why Roland Garros' traditional clay courts can pose a greater heat risk than the same air temperature would on a different surface.

Interestingly, other research from Perry Weather suggested that grass, artificial turf, and regular tennis courts showed similar heat patterns at some locations. This underscores why measuring heat directly at each venue is so important rather than assuming one rule fits everywhere.

The Broader Picture

What the French Open is doing fits into a wider shift in sports safety. High school athletic programs use WBGT measurements to decide how often athletes get water breaks, whether they can wear full equipment, and how long practices should last. Weather organizations like the California Interscholastic Federation have been using this method for years.

For decades, coaches and organizers relied simply on air temperature to judge heat risk. Over time, researchers and sports medicine doctors recognized that approach missed too much — humidity, sun exposure, and wind all change how heat actually affects the human body during exercise. Better measurement tools led to better safety rules.

The broader context here is worth noting. We have seen similar shifts before in sports safety — think of how concussions in football went from being shrugged off to becoming a major concern once the science was clear and legal liability became real. Heat management in athletics appears to be following the same arc: growing awareness, better tools, and gradual adoption of tougher rules.

Roland Garros' action may push other outdoor sporting events — marathons, cycling races, and other endurance competitions — to adopt similar heat-monitoring systems. Because the French Open is watched globally and covered extensively by sports media, changes there tend to influence how other major events handle similar problems.

One detail stands out about how Roland Garros is handling this. The tournament is using infrastructure — the retractable roofs and air conditioning on its main courts — to keep competition going during extreme heat rather than just cancelling matches or moving everything indoors. That balancing act, between safety and keeping the event running, may become a model for other outdoor sports as extreme heat events become more frequent. It is a practical solution that does not require abandoning the traditional character of the sport.