Rod Laver Arena
In 1988, Rod Laver Arena opened making the Australian Open the first Grand Slam to feature a retractable roof. The initial heat policy allowed for the roof to be closed when the temperature rose above or at the referee's discretion when the temperature rose above , but only for daytime matches and only once all singles matches could be scheduled inside Rod Laver Arena. This effectively meant that the heat policy could only go in effect in the quarterfinals or later in the tournament.