The new rule is based on the Wet Bulb Globe Temperature (WBGT), which measures heat stress in direct sunlight. It involves observing temperature, humidity, wind speed, sun angle, and cloud cover.

If the WBGT reaches 30.1C or higher during the first two sets of a best-of-three match, either player can request a break of 10 minutes to cool off.

Under the supervision of ATP medical staff, players can hydrate, change clothing, shower and receive coaching.

Play will be suspended when the WBGT exceeds 32.2C.

“The new heat rule provides a structured, medically supported approach to managing extreme heat, with the objective of safeguarding player health, while also improving conditions for spectators, officials, ball persons and tournament staff,” the statement added.