If you thought the 32-degree day in Perth felt a little odd for this time of year, you would be right.

The city recorded a maximum of 32.7 degrees Celsius at 1:04pm on Saturday — making it the latest 30-degree or above day in autumn on record.

The previous record for Perth was set on May 9, 1962, when the city recorded exactly 30C.

It was also Perth's second hottest May day on record, behind the 34.3C recorded on May 1, 2002.

The average maximum for May is 22.3C.

The unseasonable warmth, which is set to continue into next week, is due to a high pressure system in the bight and a trough of low pressure off the west coast pushing warm air from the north towards Perth.

Midge infestation

Perth's endless summer is causing problems for residents near Lake Monger, as midges swarm the surrounding suburbs.

Midges swarm on a flyscreen at a Mount Hawthorn house. ( Supplied )

Mount Hawthorn residents told the ABC the small flying insects were a nuisance — sticking to clothes on their washing lines and infesting patios.

Town of Cambridge acting chief Jason Lyon said the problem was the worst it had been in 12 years, with the council receiving about 40 complaints since April.

"A combination of environmental factors contribute to the increase in numbers — heavy rainfall over summer and above average temperatures in autumn creates ideal breeding conditions for midges," he said.

"The high rainfall has washed nutrients into the lake which in turn has led to an increase in the amount of algae within the lake.

"Combined with the unseasonal warm autumn weather, this has resulted in increased breeding, affecting the residential areas adjacent to Lake Monger."

The council said it was investing in the rehabilitation of the lake shorelines to improve water quality.

A stark contrast to the east

Sorry, this video has expired Flash floods tear through Hobart after record rain. ( ABC News )

Perth's warm week is in stark contrast to the weather on the other side of the country, with low pressure system bringing wind, snow and icy temperatures to most of south-east Australia.

Hobart is mopping up after the worst storm to hit southern Tasmania in years.

Cars floated down Hobart CBD streets and homes and businesses were evacuated as flash-flooding hit the city following record rainfall.

While Melbourne did not experience the same weather extremes seen in parts of Tasmania, more rain fell in 24 hours to 9:00am on Friday morning than in the entire month of April.