An unstable showery and snowy south to southwest flow dominates New Zealand today, with thunderstorms set to spark up in the afternoon in some parts.

Most of the unsettled weather will have passed by the end of today, with a mix of showers and sunshine through the rest of the week before more settled conditions arrive this weekend, MetService said in its latest weather update.

As of 10am on Tuesday morning, there were 18,782 lightning strikes reported across the country, many happening early in the morning as an active front passed over the North Island.

Meanwhile, in the South Island, snow has been reported almost to sea level as far north as Christchurch, with Mount Cook Airport reporting at least 20cm of snow.

The Crown Range received between 20 and 30cm of snow, while the Milford Road received 10cm.

Through to 4pm today, up to 4cm is expected to fall at the Desert Road summit.

Similarly, areas above 600 metres on Arthur’s and Lewis Passes are forecast to receive between 6-10cm of snow before about 4pm.

“It’s looking like a chilly night ahead for many South Island areas with everyone seeing single digits,” said MetService meteorologist Dom Barry.

“Lows of -1C for Timaru and Wānaka, and zero degrees Celsius for Christchurch will see the woolly blankets out again for sure!”

A ridge of high pressure begins to take hold over the North Island tomorrow, with westerlies developing.

This brings showers to western and southern parts of both islands during the day, which creep into the east and north of the North Island in the afternoon, while clearing in the west.

It remains mainly fine elsewhere.

Heading into Thursday, rain is forecast to persist in the south and west of the South Island, with showers lingering in the western North Island.

The sun is expected to be out in most other areas.

“A complex low-pressure system sits to the north of the country and brings some showers to Northland,” said Barry.

“The ridge goes into battle with this low and wins, keeping it north of the country, with only the edges of it impacting the Far North. This pattern continues into Friday, with many of the showers clearing up just in time for trick-or-treating on the spookiest night of the year.”

These showers remain confined to the mountains during the evening.

As for the weekend – it’s a taste of summer, with mainly fine weather for most and some afternoon showers inland.

Temperatures hit the high teens and early twenties for everyone – quite the contrast to the Octoberfest of weather we have just had!