Play to start earlier at Australian Open as Melbourne braces for a heatwave

With temperatures set to soar across the long weekend, there's a chance play at the Australian Open could be suspended.

Matches will start an hour earlier than usual on day seven in an attempt to avoid as much of the heat as possible.

The tournament has already seen some impacts of heat after a ball girl collapsed on court when Zeynep Sönmez took on 11th seed Ekaterina Alexandrova.

Victoria, along with much of the country's south east, will experience a prolonged severe heatwave from Saturday, which has the potential to break all-time temperature records.

Melbourne is tipped to hit 40 degrees Celsius on Saturday, with a total fire ban declared for the entire state.

A cool change will then move through, but it won't last long. The heat will ramp up again on Tuesday, with the temperature forecast to reach 44C in the outer suburbs of Melbourne.

It will be unavoidable for athletes and revellers at the tennis, but there are some things they can do to keep cool in the heat.

How does the heat affect players?

Thermal physiologist Matt Brearley said while well-trained athletes were able to better tolerate heatwaves, they still had limits.

"Our bodies are like internal combustion engines — the harder we work, the harder we play, the more heat we produce," Dr Brearley said.

"For some people, getting up into the high 38s, low 39s, they'll start to see symptoms such as headache, fatigue, irritability and nausea.

"If it gets much higher, they'll probably see some central nervous system impairments such as confusion, delirium … [It's] extremely dangerous at that point, because the body and the brain is impacted."

He said athletes were "extremely heat acclimatised" as a result of their training, but could still experience heat stroke, which could be deadly.

It's why heat policies exist.

What is Tennis Australia doing about the heat?

Extreme heat at the Australian Open is not uncommon. Every year, there are at least a few days where temperatures are above 30C during the tournament.

In 2014, a four-day heatwave — which melted bottles courtside — saw a record number of players pull out of the tournament and led to many complaints from athletes and spectators.

Sporting events, including the Australian Open, use a metric called the Wet Bulb Globe Temperature (WBGT) to measure the impact of heat on an athlete.

It's a comprehensive index that takes into account the temperature, humidity, wind speed, sun angle and cloud coverage.

In 2018, a device called an environmental management unit, or EMU, was developed because nothing was available at the time to measure these elements by the side of a court.

It collects data, which is then put into an algorithm before it is translated into a five-point scale called the AO Heat Stress Scale. It looks similar to the fire danger rating scale.

The scale would then trigger certain rules in relation to heat for players.

At the beginning of the 2026 season, the Association of Tennis Professionals (ATP) introduced a new heat rule.

It includes a 10-minute cooling break for when the WBGT reaches 30.1 or higher during the first two sets of best-of-three singles matches.

If activated, a 10-minute cooling break after the second set can also be requested by either player.

Under the new heat rule, play will be suspended when the WBGT exceeds 32.2C.

"During the break, players may utilise cooling measures, hydrate, change clothing, shower and receive coaching, under the supervision of ATP medical staff," the ATP said in a statement when the new rules were announced in December.

It said the new rule aimed to safeguard player health, "while also improving conditions for spectators, officials, ball persons, and tournament staff".

If the scale reaches five, matches will be called off.

Tennis Australia chief executive Craig Tiley said there may be a break in the tennis on Saturday in the late afternoon due to the heat.

"Our Bureau of Meteorology experts are telling us probably sometime [on Saturday] afternoon … between 3 and 6pm, we could be at that point," he said.

How can spectators stay cool?

Water misters are littered throughout the grounds and there are plenty of shady places, particularly near hydration stations.

Dr Brearley said while hydration was essential on hot days, by itself it may not be enough for a lot of people.

"Most people want to cool down when they get hot," he said.

"But what you can do is actually cool our body before you get hot and give yourself a greater window for heat storage and [for athletes] improved performance early in the match."

How to do that, he said, was by pre-cooling.

Athletes will often jump into an ice bath or ingest crushed ice drinks before they expose themselves to heat and spectators at the tennis can achieve the same effect by eating icy-poles or slushies.

"Melting ice in your body, changing it from a solid to a liquid, requires a phenomenal amount of heat," he said.

"That's our body heat that melts the ice and so basically, by transferring body heat to the ice, you're creating a heat sink internally."

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