Weather: 'Peak spring' to lay another beating on New Zealand

The weather is preparing another "one-two punch" with warnings "peak spring" will continue to land blows for another month.

After one of the chilliest months on average since 2017, NIWA says Kiwis shouldn't put away their winter woollies just yet.

"A mild weekend is ahead, but a one-two punch of cold southerlies is expected next week!" it said on Facebook.

"However by mid-October, a much warmer pattern will likely be taking shape over NZ."

WeatherWatch says Monday and Tuesday are expected to "produce miserable conditions with sub-zero wind chills for a time and Wednesday may linger cold too for a time".

"The cold air next week is mostly in the lower half of the South Island and goes from Monday to Wednesday with single-digit highs in some areas," it wrote on Facebook.

"Snow flurries are possible to 100 or 200m around northern Southland and perhaps some parts of Otago for a brief time but again whether you get a flurry or not is almost beside the point, it's the cold + dampness that is the real issue for newborn lambs."

And MetService says the blast of cold air and spring snow could mean a "danger to young livestock", "road closures" and "rapid drops in temperature", especially inland parts of the South Island and the Desert Rd.

WeatherWatch says it's a sign that "peak spring" will continue for another month yet.

"From the middle of September to the end of October is when spring is traditionally at its most chaotic, energetic and changeable.

"As we go through October we should see two things - high pressure trying to move in from Aussie for northern NZ and an uptick in westerly winds for many regions further south. 

"We have cold snaps in the mix with sub-tropical flows too. These mixes of warm and cold air can produce localised dramatic weather (a sudden downpour or thunderstorms, hail or gales suddenly). Spring really is the Jekyll and Hyde season."