Play has been suspended on the outside courts at the Australian Open after the Heat Stress Scale reached 5.
Play continued until the end of an even number of games or the completion of a tie-break.
No new matches will be called to the outside courts.
Play has also been suspended on outdoor practice courts.
On Rod Laver Arena, Margaret Court Arena and John Cain Arena, play has continued under closed roofs.
The AO Heat Stress Scale takes into account air temperature, radiant heat (strength of the sun), humidity and wind speed, which affect a player’s ability to disperse heat from their body.
Those factors are measured in real time across five different locations across the Melbourne Park precinct.