It's beginning to feel a lot like Perth Christmas as the mercury pushed past 40 degrees celsius on Saturday afternoon.

According to Bureau of Meterology's Neil Bennett it is the first time Perth has hit 40 since January 26, 2017, when it got to 42 degrees.

Perth's maximum was 40.9 degrees while Pearce was the city's hottest suburb at 41.6 degrees.

Gooseberry Hill was also scorching at 41.3 degrees.

The closer to the coast, the lower the temperature.

At Rottnest Island it only got to 37.9 degrees while Mandurah only hit 35.1.

The next few days were forecast to hit the mid 30s while the Bureau predicts 33 degrees for Christmas day.