An extremely hot air mass will build over Western Australia towards the end of this week, causing Perth to extend its record for the number of days over 40°C in a single year.

The absence of monsoon cloud and rain will allow heat to build over northwestern Australia in the next few days. This heat will also be enhanced by the year’s maximum solar exposure being so close to the summer solstice in the southern hemisphere.

Forecast models suggest that temperatures will reach the mid-forties in WA’s Pilbara and Gascoyne regions on Thursday and Friday, before possibly pushing into the high forties on the weekend and early next week.

Some models are showing potential for maximum temperatures to reach around 48 to 49°C in the Pilbara or Gascoyne on Sunday or Monday, which would be some of the highest temperatures in Australia this year.

Image: Forecast maximum temperature over the northwest of WA on Sunday, December 22, 2024.

The hot air mass will also spread further south from the weekend and cause temperatures to spike in Perth. The city is forecast to reach 40 to 41°C on Sunday and Monday.

Prior to this bout of heat, Perth had already registered 10 days over 40°C so far this year. This is the highest number of 40°C on record for a single year, beating nine days from 2007. This record could be extended to 11 or 12 days after next Monday.

Image: Forecast for Perth on the Weatherzone app, valid as of Thursday, December 19, 2024.

The looming hot weather will contribute to High to Extreme fire danger ratings over a broad area of WA in the next few days. Visit https://www.emergency.wa.gov.au/ for the latest information on fires across the state.