As Perth's extended summer continues to nudge records, the weather has proved a double-edged sword for those whose livelihoods depend on it.

Perth is experiencing its warmest week this late into autumn in 33 years, with the city recording an average maximum temperature of 25.4 degrees Celsius in the seven days to May 22.

And it's not over yet, with Wednesday and Thursday forecast to hit the high 20s.

That will make it the warmest week this late into May since 1985, when a mean maximum of 25.6 degrees was recorded from May 20 to 26.

The warm weather so close to winter has provided a boost for beachside businesses after a cooler-than-usual summer.

The manager of Social restaurant at Hillarys Boat Harbour, Tahni Anderson, said more people had come through the doors than usual for this time of year, especially in the mornings and afternoons.

"We're right on the jetty, we've got a whole panoramic view of the water and I think it complements us if the weather is better. I think it's definitely making people come out more," he said.

"As soon as it's wet and gloomy everyone wants to stay at home, it's a lot harder to get out of bed.

"It's crazy how we went from the (cool) summer and thought we were going into darker days with winter and we've just had this nice surprise of great weather."

Social restaurant at Hillarys Boat Harbour has seen a steady stream of customers thanks to the ongoing good weather. ( ABC News: Irena Ceranic )

Extended heat leaves winter garments shelved

Not everyone is reaping the benefits of a warm autumn.

The unseasonable warmth has not been ideal for retailers, whose racks are lined with woolly jumpers and thick coats.

Claudia Princi, owner of clothing store Department — one of the few remaining independent clothing stores on Beaufort Street in Mount Lawley — said people were not rushing to buy winter stock.

"The heavier winter (clothing) is not moving or being thought about as much as it usually is this time of year," Ms Princi said.

"I think people start to question whether we need those things as much now given the climate.

Clothing store owner Claudia Princi said she had adjusted her stock orders to reflect Perth's changing climate. ( ABC News: Irena Ceranic )

"It's only cold towards the end of July, August and September."

Clothing stores generally start stocking warm clothing in February and orders are made up to a year in advance.

But Ms Princi said she had started adjusting her orders to better suit Perth's adjusting climate.

"I think we just have to be a bit more cautious about... what we're choosing to put in stores in what months for Perth," she said.

"It would be nice for it to be a bit cooler from a business perspective."

Perth's first blast of winter will arrive at the end of the week, with a strong cold front forecast to bring gusty showers and thunderstorms to the west coast.