The White Giraffe Series (abridged)

When she is 11 years old, Martine is orphaned and sent to live with her grandmother on a game reserve in South Africa. Her grandmother seems strangely unwelcoming, and Martine has a difficult time settling in at her new school, where she is conspicuously an outsider. But she has an ally in Tendai, one of the keepers on the reserve, from whom she learns the lore and survival techniques of the bush, and in Grace, who instantly senses there is something special about Martine.

It's June - winter in South Africa, and Martine and her grandmother are enjoying a cold but beautiful walk along the beach when they find a stranded, dying dolphin.