A week-long low pressure system in the Tasman Sea will cross New Zealand overnight and into Wednesday bringing showers, isolated thunderstorms to the west or north and more mild weather for many areas for another day.

By the end of Wednesday – and across the next few days – a number of cold fronts approach New Zealand with colder air behind each one.

There will be surges of sunny, mild, weather in the east of both islands at times but the general theme is for the air to get colder and colder in the days ahead.

By Sunday a large low may engulf NZ with rain, wind and then snow lowering on the hills and ranges. Not yet locked in but we have our first detailed weekend forecast out today and it does show a lot going on weatherwise this weekend and into next week.