Australia Weather News

A West Australian town 445 kilometres north of Perth was so hot on Sunday that residents' thermometers were breaking.

Helen Ansell from Mullewa, 100km inland from Geraldton, discovered her thermometer had broken in the sun.

"Yesterday it was something else. You couldn't even stand outside for two minutes, it was really unbearably hot," she said.

"The thermometers I had only went up to 50 [degrees Celsius] , and they went right up to 50.

"We put it in the sun out of interest and it just went right up to about 55 and then exploded."

The nearby regional city of Geraldton recorded its second hottest December day on record with 46.5 degrees.

However, several locals of surrounding towns and suburbs captured much higher readings on their own temperature gauges, sharing them on the ABC Midwest Facebook page.

They included highs of 50 in Northampton and Waggrakine, 48 in Moora, and 49 in Strathalbyn.

Ms Ansell said she and other local mums took to the local swimming pool in a bid to escape the heat.

Mixed reactions to record heat

On the coast, Geraldton's usual beachgoers avoided the middle of the day heat.

Yvonne Causer said her family stayed in air conditioning and found indoor activities to entertain young children.

"Movies, we had lots of playdough out, slime out, to get us through," she said.

"We didn't come down [to the beach] 'til half past four in the evening and it was beautiful and still down here, which is not like Geraldton."

Geraldton local Donna Collis said it felt hotter than ever before, although she and her family did not mind it much.

"We came out in the morning and lied low in the afternoon," Ms Collis said.

"We notice Geraldton is definitely getting hotter.

"As children we'd play down on the foreshore here on 40 degree days. Now it's up to 46."

Mark Collis and his mother Muriel said they liked the heat.

"I've worked outside most of my life, on stations and for a mining company, so I'm used to the heat," Mr Collis said.

Other residents such as Angie Parker, who moved to Geraldton from Perth a year ago, were less acclimatised.

"Probably from about 8:30am I had the whole house shut and couldn't even leave the house, it was so hot," she said.

"It was like an oven outside.

"I'm from Perth so maybe that's why it got to me."

Dr Karl weighs in

Science communicator Dr Karl Kruszelnicki said thermometers can break if the fluid inside expands more than the gauge is designed to take.

"There's a liquid in it that expands. If [the thermometer's] made of glass, it breaks," he said.

He said regulating the environment around thermometers was important to create a reading that can be more accurately compared to other measurements.

"Way back we invented a thing called a Stevenson Screen," Dr Karl said.

"It's a box, it's got double-louvred walls on all sides, and it's got a thermometer inside in the shade.

"It's used all around the world as the standard way of measuring the temperature.

"Of course you could just leave the thermometer out in the sun, but that would be different from place to place, so that's why they use the Stevenson Screen as a standard."

The Bureau of Meteorology confirmed it used Stevenson Screens on all its temperature measuring instruments.

"Official bureau instruments are sheltered from solar radiation — both direct or reflected," a spokesperson said.

"Bureau sites use a free-standing louvred [Stevenson Screen] which allows airflow but protects the instruments from sunlight.

"Instruments that are shaded from above but not protected from reflected solar radiation from below will typically over-read by about 1 to 1.5 degrees relative to the bureau standard.

"Instruments close to a building [for example, under eaves on the side of a house] will also be influenced by the heating of the building materials and may over-read by several degrees depending on their exact position."