The policy: Wimbledon operates a specific Extreme Heat Policy designed to safeguard players when temperatures and humidity levels rise.
Historically, this rule applied primarily to the women's draw, but a standardised heat rule is now uniformly enforced across both men's and women's singles events.
The trigger threshold: The heat rule is not determined by air temperature alone.
Instead, it is triggered when the Heat Stress Index — measured using the Wet Bulb Globe Temperature (WBGT) — reaches or exceeds 30.1°C (86.2°F).
How the index is measured: This index takes into account air temperature, humidity, wind speed and the heat radiating directly off the grass surface.
