Weather: It has been a sorry start to summer but will it be a wet or sunny Christmas?

Summer is misfiring. Multiple false starts and washouts have left us all a little weary. 

And it's not just the cost of living crisis threatening to spoil Christmas this year, the weather could also play its part.

But as we lament the poor start to summer, is it really that unusual? Or are we just quick to forget how it has been in the past?

I hate to be the bearer of bad news - but December is always a little 'meh'. In fact, last December started in a similar fashion - maybe even worse than this year.

2020 however was very dry and void of any sort of rain, let alone intense thunderstorms and torrential downpours. But all three were during a spell of La Niña - so why have the last three been so different?

Multiple drivers affect New Zealand's climate - not just ENSO (El Niño Southern Oscillation).

We have another influencing driver called IOD, or the Indian Ocean Dipole. This affects the number of low-pressure systems that form in the northern Tasman Sea. Currently, the IOD is in a negative state, which leads to an increase in these rain-making systems. And even though La Niña does have a specific list of weather conditions it tends to influence, every La Niña phase is different.

So generalising - La Niña dishes up warm air and coastal sea temperatures, and winds favour the northeast.

As for the rain? Higher than normal for the northeast of the North Island, and less than normal for the south and west of the South Island.

It doesn't mean that this is our daily weather - it's an overall trend for the season - which is three months long.

The summer solstice is next Thursday (December 22), and that marks the start of astronomical summer. Will that also mark the start of the 'summer' weather? Watch the video to find out!