I live in New Zealand, it's winter here now, and it's freezing! How did a stone-age peoples, with access to only feather cloaks (no large mammals to skin) manage to survive the winter months, especially in the south of the country? Did they just not go outside?
Maori made far more than just feather cloaks! There were indeed mammals to skin (dogs and seals), but many of their clothes were made from fibrous plants. During the winter months, a rain cape, or Pake would shield you from the elements. Many of these textiles are still being made today.
If you'd like to see some images, check out the excellent online resources Te Papa has pulled together.
Bear in mind that very few Māori lived in the South Island pre European contact. So they likely weren't dealing with sub zero temperatures.
I haven't got the link right now, but Te Ara encyclopaedia has a good section on Māori housing. Communal sleeping houses, expertly thatched with harakeke and other plants, low roof and a hearth.
What's the temperature like?