Australia could face a scorcher of a summer if this year's heatwaves in the northern hemisphere are replicated south of the equator.
But despite Aussies previously experiencing hot summers, experts say the nation is unprepared for what's to come with many predicting the first El Nino in three years.
Sweltering Cities, which advocates for more liveable, equitable and sustainable cities, is calling on all levels of government to take action before summer hits to ensure people are kept safe and cool.
The non-profit proposes councils delegate "community cool centres" as respite for people who cannot stay cool at home on hot days, while state governments could make heatwave safety part of renters' rights.
But most crucial will be a national heatwave plan to ensure responses are co-ordinated across the country.
The federal government must also ensure the health system is summer-ready, from major city hospitals to remote services.
Sweltering Cities executive director Emma Bacon said extreme global heatwaves should be a wake-up call for Australia.
"Regardless of whether we have El Nino or not this year, the heat we're going to experience in coming summers will be worse than any we've felt before due to climate change," Ms Bacon said.
"They will be the hottest summers of our lives."
Governments cannot wait until after a deadly summer to take action, Ms Bacon added.
"The type of heatwaves we should expect won't be isolated to one local government area or even one state at a time," she said.
"That's why we need action at every level of government."
The group's plan also calls on the government to do more to tackle emissions-related climate change and stop future temperature increases.