The temperature will once again soar above 40ºC in Perth from this weekend, putting the city on track to break its record for the most 40ºC days in a single month.

Abnormally high pressure to the south of WA has caused a relentless flow of hot easterly winds across WA during the first half of February.

This weather pattern has delivered repetitive bursts of extreme heat in Perth, with the city already registering five days above 40ºC in the first half of February. In an average February, Perth would typically only see one day over 40ºC.

This month’s high frequency of 40ºC days is on track to be record-breaking. In data dating back to 1897, Perth has only seen as many as six days at or above 40ºC in a single month, which occurred in January 2022.

With another wave of heat expected to hit Perth this weekend and early next week, the city is forecast to reach around 43ºC on Sunday and 42ºC on Monday. Even Tuesday has a chance of hitting 40ºC at this stage.

Image: Forecast maximum temperature on Sunday, February 18, according to the ECMWF-HRES model.

This next batch of hot days should take Perth’s running tally of 40ºC days to seven or eight so far this month. This would easily break the previous record of six days in January 2022.

One reason for Perth’s abnormal heat this month has been a predominantly positive Southern Annular Mode (SAM), which has kept cold fronts well to the south of WA. There has also been a region of abnormally high sea level pressure located to the southwest of Australia, which has enhanced easterly winds across WA.

The background warming influence of climate change is also likely to have contributed to this month’s heat in Perth. According to data from the Bureau of Meteorology, Perth Airport’s average maximum temperature during summer has increased by around 3ºC since 1910.

Image: Average summer maximum temperature at Perth Airport between 1910 and 2021. Source: Bureau of Meteorology