Christchurch is the largest city of the South Island of New Zealand. The seasons there are the reverse of Germany. Abbasi Travels can search flights for you.
Summer (December to February) is the warmest time. Winters (June to August) are cold, with frost. 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.