It's tough enough walking 28km a week while rough sleeping without the dry heat of summer.
But El Nino, coupled with climate change drawing up temperatures, is making the long, windy path to survive on the streets more difficult this summer, charity Wayside Chapel warns.
Every night, more than 122,000 Australians sleep rough - the equivalent of more than a quarter of the population of Canberra.
Rough sleepers often stay alert overnight out of fear of being assaulted, leaving daytime the only time for rest, Wayside chief executive Jon Owen says.
That's particularly the case for those new to the streets, something that appears on the rise amid a crushing rental market, rising living costs and a doubling in demand for Wayside's services.
"You're trying to catch a nap in the middle of a 35C day and you're already at your wit's end," Mr Owen tells AAP.
"There's exhaustion and dehydration.
"It really does a number on your body, on your feet.
"Climate change and the cost-of-living increases that have really hit people, you're seeing that all come together on the streets."
Former homeless man Scott Endersby says rising temperatures make many basic tasks more difficult.
"It's more daunting in the heat - I know I didn't want to go to interviews in the summer," he told AAP.
"I'd rather just kick back with a cardboard box and sleep in a driveway."
Having turned his life around, the 49-year-old is the face of an initiative getting people to take on a 28km trek across Sydney on Saturday to mimic the average distance a homeless person makes to reach vital services each week.
The Long Walk Home also raises critical funds for Wayside.
Mr Endersby credits the charity's services and support worker Joe Ireland for helping him gain a footing in the private rental market, secure his driver's licence and keep him on the straight and narrow.
"I had a bad day a couple of months ago ... I came back to Wayside and he just looked in my face and said 'what's wrong?'
"He straightaway knew what was going on ... we need more like that in society," the demolition worker said.
For those who would like to support but cannot undertake the walk, a free virtual walk challenge allows participants to go at their own pace across the course of a week.
Australian Associated Press
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