Australian seasons work like this:
summer season in australia
Summer
Australia's summer is officially from 1 December to 28/29 February.
The Australian Summer corresponds to Winter in the USA. When it is summer in the US it is winter in Australia and vice versa.
Christmas Day occurs in Australia's summer. This is because when it is winter in the northern hemisphere, it is the opposite season (summer) in the souern hemisphere, where Australia is located.
Summer
Winter.
Winter
winter
Summer
SUMMER
Summer