Weather Watch: Wintry weather has ended

Spring is all about warmer days, more sun, but still the odd snowy cold snap - like we saw at the start of this week. Photo / NZ Herald

I was having a discussion with someone the other day who predicts the weather in more of an alternative way than I do and was claiming that winter is still well and truly with us.

I've also had interviews with reporters here at the Herald and at the Radio Network asking when this "wintry weather will end". Thing is - it has ended.

It's a common assumption that stormy weather = winter. But actual winter = cold. Spring = stormy/unsettled.

Over the many years I've covered the weather I've found the spring season often creates this confusion. I'm not to sure what many expect spring to be but spring is a turbulent season - often more violent than winter. The sun is spending more time in the Southern Hemisphere and that extra heat reacts wildly with the wintry air still remaining in the roaring forties. The result - thunderstorms, gales and big lows.

Spring is all about warmer days and more sun, but still the odd snowy cold snap - like we saw at the start of this week. Most Septembers and Octobers we have a cold snap that comes through and drops snow to low levels - even in the North Island.

But the clear difference between "winter" and a "wintry snap in spring" is basically the time frame of the cold air - just how short-lived it is. On Monday many northern centres struggled to reach the teens - those that did didn't climb much over 13. But just a couple of days later most were in the 20s. This is why we don't consider this weather "winter like".

The cold snap that killed all those lambs in Southland last month was certainly severe, but also very isolated - in fact just a little further north in Canterbury the skies were clear and the weather mild. Not winter at all.

The rest of October looks far more settled in the upper North Island but those windy conditions will continue off and on for central and eastern areas. I think warmer conditions will continue to prevail too along with drier weather in the east.

Also - keep in mind that while September was certainly stormy, it was hardly wintry - with the average temperature being average or above average for most regions, as predicted by NIWA.