Niwa forecasts cooler temperatures and frosts as El Nino pattern ushers in drier months

Cool, dry days are on the way for many over the coming months, according to experts. Photo / 123rf

Meteorologists are predicting an earlier-than-usual El Nino weather pattern will bring “quite striking” drier and cooler conditions heading into winter, with frosts to hit as early as next week.

It’s shaping up to be a colder, but drier than average, next few months across most of the country with humid and wet La Nina systems on the way out.

And according to a seasonal climate outlook from Earth Sciences (formerly Niwa), the long-term average temperatures across New Zealand are expected to be below average.

Principal meteorologist Chris Brandolino told the Herald the cooler-than-average, dry spells were “quite striking”.

“A rapid transition from La Nina to El Nino ... is on its way, which has an unusual whiplash effect when it goes from one driver to the next.”

He said La Nina and El Nino acted as “climate drivers” of the overall theme of weather, with the former tending to produce warmer, humid days and the latter cooler winds that tended to drive drier, colder weather.

“This is what you could call mother nature’s personality rather than her mood. We aren’t saying ‘winter will definitely be dry and cold’, we are saying the weather is becoming consistent with what a strong El Nino pattern brings.”

While the peak of dryness wouldn’t be until nearer the end of winter, frost could be seen as early as next week.

Brandolino said La Nina increases the odds of big rainfall events, including the ones we’ve had this year.

In January, heavy rain caused a landslide at the base of Mount Maunganui, killing six people.

Then, in mid-February, a man was killed when his car became submerged in flood waters near Ōtorohanga.

Last month, Cyclone Vaianu caused widespread destruction to eastern North Island towns, with Ōhope bearing the brunt.

Brandolino said the southwest coast of the South Island was the outlier for winter, with normal or above average temperatures set to bring a “wetter” approach to the area.

Kiwis in other parts of the south have been advised to keep an eye on the land before the growing season begins.

Soil moisture anomaly map shows variations across the country. Photo / Niwa

“The South Island will be a lot drier than the north because it hasn’t had as much rain to keep the soil wet.”

Brandolino said out-of-season fires and low water tank levels were also things to consider with less than average rainfall expected.