Sydney's weather has produced another first - the first seven days of spring all topping out above 21 degrees.
Sydney Airport recorded a maximum of 32.2 degrees on Saturday, while the city posted 31 degrees, the third highest on record for the so-called warming seasons and the warmest this early in spring.
Sydney's warm spell could last another 10 days, said Rob Sharpe, meteorologist with Weatherzone.
The long-term record average maximum for Sydney, set in 1980 at 23.3 degrees, may also fall.
Australia has just experienced its warmest 12 months since climate records began and NSW recorded its second warmest winter, eclipsed only by that of 2009. Sydney's winter, though, was its mildest.
''There is definitely a good chance we will set a record for September,'' Mr Sharpe said.
With retailers reeling from a mild winter that junked much of the selling season, the executive director of the Australian Retailers Association, Russell Zimmerman, said store owners are hoping for a consistent build-up to a hot summer.
"Retailers are a bit like farmers,'' he said. ''Farmers complain about it being too wet or too dry, or too hot or too windy."
Craig James, chief economist at CommSec, agrees balmy weather can be a bonus for the economy provided "it gets warm at the right time". Outdoor-related businesses, from restaurants to swimming pool builders, will welcome the warm weather, Mr James said.
Canberra's post-election leaders would be wise not to take a spring-heeled economic revival for granted.
For one thing, the weather is unlikely to remain quite so clement.
Blair Trewin, senior climatologist at the Weather Bureau, recalls the spring of 1987 also started out warm: "Then a couple of weeks after that in October, Canberra had one of its two most significant snowfalls in the last 30-plus years."