Sydney is the largest city of Australia. The seasons there are the reverse of Germany: it is summer in December to February. Abbasi Travels can search flights for you.
Summer (December to February) is warm. Spring (September to November) and autumn (March to May) are usually mild. Winter (June to August) is cool. Figures and seasons differ between sources, so treat this as a rough guide.
Whether you need a visa depends on your passport and on how long you stay. Open our visa check to see what we have researched, and always confirm on the official government website before you book.