If you think it's cold now, wait till you see the temperature this afternoon.
Icy Antarctic air is moving up the country, but a second, more intense front will make it even colder later today.
Temperatures are forecast to drop by up to 15 degrees in less than 18 hours in some places.
Snow is falling on South Island roads, and could fall to sea level at Christchurch and further south later.
NIWA meteorologist Chris Brandolino spoke to Corin Dann.
