The scale ranges from one to five, with one denoting “temperate playing conditions” and five triggering the suspension of play, the governing body said in a statement on Saturday.
Men will now join women in being permitted 10-minute breaks during extreme heat conditions, tournament director Craig Tiley said.
“In the men’s singles a 10-minute break will be allowed after the third set when a four (4.0) is recorded on the AO HSS (heat stress scale) prior to or during the first three sets of the match,” TA said.
When the scale reaches five, the tournament referee can suspend matches on outside courts and decide to close the roof on the three show-courts, Rod Laver Arena, Margaret Court Arena and Melbourne Arena, which was formerly known as Hisense Arena.
The updated policy also introduces 15-minute breaks for wheelchair players.