have a theory – a strange analogy really – that describes the change of seasons. It’s called the “step by step” theory. Basically, think of summer as the top floor of a house, ground is winter…autumn and spring are floors (or wings) on either side half way up. (Terrible building design I know…must be from the same architects who brought us leaky homes).

Right now, most of us are on the top floor, enjoying summer-like temperatures. However it’s becoming clear – especially at night – that we are now well and truly moving away from the longest day of the year, which was back around December 22.

We’re heading down to the second floors – choosing the Autumn side. We’re not quite there yet, but we’re certainly moving down the stair case. The steps aren’t the same size either. Some are short and sharp… others long and only slightly lower than the last.

If my graphic design skills from High School are anything to go by, it wouldn’t surprise me if I built this building.

I know this analogy appears to have been written in the same way lyrics to Beatles songs were written… but the description is quite apt. The change of season obviously doesn’t just happen overnight. The changes tend to happen in segments, or in this case ‘steps’.

This Thursday is a good example. We’re going to see a cool change heading up the South Island on Thursday and then fading out as it heads into the North Island. It will see places like Invercargill and Dunedin fall from the 20 degree mark for their daily highs to the low teens. It will then plateau out in the mid to late teens. So when you look at this week and next week you’ll see it stepping down a couple of degrees. It may hold like that for another week or two…but then it will do it again. Some steps down will be bigger than others, depending on the cold changes.

I guess it’s fair to say that occasionally it will step back upwards. Hmm…the more I describe this that weirder it sounds. But I’m sure you get what I’m saying.

We’re in the change of seasons now. So as we step down to winter we’ll see more drops like the one at the end of this week….then a plateau effect… then another drop…until in just over four months time we reach the bottom floor. Fumble around in the darkness for a bit, until starting on the other side, back up to spring and then on to summer once again.

– Philip Duncan, head weather analyst

What do you think?
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