New Zealand Forecast – Rough Weather Wed & Sun, Snow & Sunshine Between Times
Published early Wednesday, 17th September 2025
We’ve got another mixed bag of weather on the way. First, a strong front moves up the South Island on Wednesday and the North Island on Thursday, bringing heavy rain and strong winds. Canterbury, in particular, will be a write-off with severe gales expected to keep most ski fields closed.
However, a cold change trailing the front will bring a top-up of powder, followed by a nice, sunny ridge for the South Island on Friday and Mt Ruapehu on Saturday – these will be the picks of the bunch. Conditions will deteriorate again as another strong front moves up the country from Saturday night through Sunday.
Wednesday 17th September
Hang on to your hats, it’s going to be a wild and windy day for the South Island. A strong front spreads heavy rain northwards throughout the day, with northwest winds reaching severe gale force in exposed areas, especially in Canterbury where most ski fields will be closed for the day.
Behind the front, winds back off a touch, rain eases to showers, and snow levels start to drop. For the Southern Lakes, this will happen during the afternoon, and for Canterbury, in the evening.
Mt Ruapehu will be fairly cloudy with a few light spits of rain as northwest winds strengthen, reaching gale force in exposed areas before the day is done.
Thursday 18th September
The odd snow shower over the Southern Lakes becomes more widespread late afternoon as brisk westerlies change to a colder southwesterly. The snowfall clears at night, leaving daily totals of around 5 to 15cm.
In Canterbury, snow showers spilling over the Main Divide clear early for a mainly fine day as gale northwest winds ease. A cold southerly change arrives around closing time, giving ski fields here a dump of between 5 and 20cm of powder, with Mt Hutt likely to be near the top of that range.
The strong front crosses the North Island, bringing heavy rain and gale northwest winds to Mt Ruapehu until the afternoon. Then, showers and sinking snow levels will continue through the rest of the day as colder winds from the west arrive.
Friday 19th September
Sunny skies and a fresh layer of powder will make for a cracker of a day for South Island ski fields as a ridge of high pressure passes over. Northwest breezes develop, and there’ll be some afternoon high cloud over the Southern Lakes.
A cold southerly whips over Mt Ruapehu early in the morning, bringing snow showers to low levels. The showers clear in the afternoon as the winds begin to ease.
Saturday 20th September
Cloud gradually builds over the South Island and northwest winds strengthen, reaching gale force in exposed areas of Canterbury as the next front approaches. The front moves up the South Island at night, bringing heavy rain and mid- to upper-level snow.
The ridge passes over the North Island with sunny skies for Mt Ruapehu and a developing northwest breeze.
Sunday 21st September
The heavy rain and mid- to upper-level snow clears the Southern Lakes early and then Canterbury later in the morning or afternoon as the front continues northwards, leaving partly sunny, partly cloudy skies and potentially deep, deep powder about the upper slopes. Severe gale northwesters also back off behind the front but will remain at gale force in exposed areas. A surge of cold air at night will bring an extra dusting or small top-up of snow to the Southern Lakes.
On Mt Ruapehu, cloudy skies and strengthening northwest winds will lead into rain as the front approaches from the south.
Extended Forecast
The weather will remain unsettled next week with another busy schedule of weather systems lined up. Models are consistent on this but differ in details. However, we can expect changeable conditions with strong winds and bouts of rain/snow interspersed with periods of calmer, sunny spells. Through it all, snowfall accumulations will gradually build, with substantial weekly totals on the cards.
That’s all from me today, folks. I’m sending out these forecasts every Monday, Wednesday and Friday throughout the season. Have a great couple of days, and I’ll see you back here on Friday.
Grasshopper
