Weather Watch: As low as it goes

Photo / Sarah Ivey

Is this as cold as it will get this year? Quite likely, yes.

Overnight lows have plummeted this week with lows getting nearer to -10 in some parts of Central Otago.

Air temperatures dropping to -5 and -6 have also been recorded along the Otago and Canterbury coastlines this weekend, affecting big centres such as Dunedin and Timaru while similar temperatures have been recorded around the North Island's Central Plateau.

And the frosty weather finally hit Auckland with cars iced over before midnight on Saturday. In fact frosts settled mid evening as the winds stopped and the clear skies remained. "SW", a regular poster at WeatherWatch.co.nz, made a good comment on Sunday about the weather - it's something I often explain to people.

"Sun out till 5pm then cloudy in winter = Win win situation
Clear night followed by Cloudy day in winter = Lose Lose situation."

What he means is that a sunny day in winter, followed by a cloudy evening means the heat is kept "locked in" overnight...so it can be several degrees warmer. On Sunday though, his "lose lose" situation came true for many in the north as a deep low started to brush New Zealand from the north east. A clear, frosty, night was replaced by thick high cloud in the morning. This is the reverse of the win win situation and ends up keeping the cold air locked in.

But as far as overnight lows go in New Zealand, we are pretty much at our normal limits. I can't imagine the overnight lows getting much worse as we sit here in the middle of winter. However the daytime highs could still take a knock - provided we get a polar blast. We are yet to have one this year. Hard to believe we are approaching the halfway mark of winter this week and still an icy southerly hasn't blasted the entire nation with heavy snow to low levels in both islands. Quite a different set up from last year.

Last year will be remembered for the massive snow falls in the North Island and lower South island - this year, without a doubt, it will be from the big rainfalls. Some farmers I've spoken to are saying it's the wettest they've encountered in 30 years.

The long range computer models pick a front moving in from the Tasman Sea later this week... which will lift temperatures as the winds pick up. It will also put a temporary end to the severe frosts in Central Otago.

And according to the 10 day computer maps there is no polar blast on the way. Spring is getting closer in the upper North Island (Waikato northwards). Daffodils are coming out, lambs are nearly here and in 4 weeks time you'll notice the extra minutes of daylight at either end of the day.

Can you tell that I'm a big fan of Spring? It's obvious when we haven't even hit the middle of winter yet but I'm already moving on to spring. Cup half full... even if it is iced over at the top.

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