"Blistering heat is a hallmark of summers in the west but this season has escalated much earlier than usual."
"Perth recorded its earliest December day above 40C on December 3, peaking at 41.6C in what was its hottest first week of summer on record.
The city has never recorded more than two 40C days in December, but that record will be challenged this week."
I think the point they are making is that it is happening earlier than usual.

