The recent spike in Perth temperatures comes as no surprise to local Noongar people.

After an unusually mild start to the year, the city reached 38.5C on Tuesday, a week after it sweltered through its warmest night in four years.

Noongar people recognise six seasons. March falls in Bunuru — the second summer and traditionally the hottest time of the year.

Barry McGuire, a Balladong Noongar man, artist and cultural educator, said Noongar people looked to changes in the environment, like the migration of birds, to signal the change of seasons.

"We are not running on a numbered calendar, it's running on an environmental calendar," he said.

"These six seasons only apply to the south-west corner of Western Australia."

Barry McGuire says the Noongar people are guided by the environment, not the calendar. ( ABC News: Charlotte Hamlyn )

The seasons explained

Bunuru runs during February and March and is considered to be the second summer.

It is preceded by Birak, the first summer in December and January. It is traditionally a hot, dry season and a time for burning.

After Bunuru is Djeran, the start of the cooler weather.

"Now in March, we are basically in Bunuru going into Djeran," Mr McGuire explained.

"The environment is telling us that we are still in a certain part of the summer."

He said the easterly winds were an indicator of change.

"It's going to stay warm for a little while, but I think towards the end of the month it's going to change and get into the Djeran."

March is the perfect time to drag a net for prawns in the Swan River. ( Supplied: Florence Roca )

Djeran is followed by Makuru, the coldest and wettest months, Djilba, the first spring in August and September, and then Kambarang, the second spring.

Bunuru is also the perfect time to try and catch prawns in the Swan River, Mr McGuire said.

"As kids around this time we used to go and drag a net through the river because the prawns were here.

"In those sultry nights we would drag the prawns.

"I don't know if anyone catches them anymore, but in my childhood this was the time."