New Zealand is on the southern hemisphere. Our winter is their summer, so New Zealanders celebrate Christmas in the warm summer sun. Many flowers and trees are in bloom at this time of the year, for example the pohutukawa. The pohutukawa tree grows on the North Island, mainly in coastal areas and has lovely red blossoms. Therefore New Zealanders call the pohutukawa their Christmas tree.
As it is usually quite warm on Christmas Day, New Zealanders can eat their Christmas dinner outside. Many people have a picnic or a barbecue. And some people even have a traditional Maori hangi: they dig a hole in the ground and heat it with hot stones. Then they put meat and vegetables into this hole, cover the hole and let the food cook inside. The hangi is served in the afternoon or evening; after the delicious meal, people often sit around and sing Christmas carols.
Some New Zealanders can't get enough of Christmas–they celebrate it twice each year: on 25 December and in July, which is mid-winter in New Zealand. So if you go to New Zealand in July, you may find hotels and restaurants fully decorated for Christmas.