With El Nino being officially declared, agencies across New Zealand are preparing for potentially severe weather.

The weather phenomenon will bring dry and windy conditions for most areas, while the western and lower South Island will get more rainfall.

In dry areas, the wildfire risk is likely to be elevated while a lack of rain will put pressure on people’s water tanks as well as the agricultural sector, Earth Sciences New Zealand (ESNZ) chief weather scientist Chris Brandolino said.

Fire and Emergency New Zealand is concerned about the conditions increasing the fire risk.

High winds could spread fires, which will start more easily because of the dehydrated landscapes, making them harder to contain, wildfire manager Tim Mitchell said.

“When you’ve got wind, that really pushes any fires along but also further enhances, I guess, that dryness of those fuels and availability of fuels to burn.”

Mitchell told the Herald that 98% of wildfires in New Zealand were started by people.

Because of New Zealand’s position, it means most areas, particularly the east and northeast, become drier while the southwest of the South Island is wetter. Photo / Christine Cornege

It is possible to have minimal fires during high-risk conditions but people must take the necessary precautions, he said.

People are “strongly encouraged” to clear their properties of vegetation, make sure fires are properly extinguished with water and always check the fire risk.

“Don’t leave those fires to smoulder for days after the main burn as you perhaps have always done.

“You might have got away with it last few seasons; you may not get away with it, or you’re unlikely to get away with it this season.”

People should also make sure their properties are accessible by fire truck, make water supplies accessible and have a plan in case a fire happens.

“There is a potential that we may have to evacuate more people this season.”

He said preparation is important because “once the smoke’s in the air it’s too late”.

Crews have been checking equipment and have increased foam and retardant stocks by 20,000 litres to carry 120,000 litres to brace for the possibility of more fires.

Fire and Emergency has also been in contact with the Department of Conservation, Forestry and the Defence Force on how they could co-ordinate their efforts.

The National Emergency Management Agency (Nema) hosted a forum last week where agencies discussed what they were expecting and how they would deal with the upcoming phenomenon.

The strongest in recorded history

ESNZ is expecting this El Nino, first declared in July, to be the “strongest in recorded history”, Brandolino said.

Although it has around 25% influence on the weather in New Zealand, its impacts can be significant.

It is caused when warmer-than-normal water temperatures slow down trade winds in the eastern Pacific that would typically carry moisture to New Zealand and Australia.

Because of New Zealand’s position, it means most areas, particularly the east and northeast, become drier while the southwest of the South Island is wetter.

No human alive has seen an El Niño event this strong. In fact, it’s possible that no human in history has seen an event this strong.

Forecasts continue to project a 3.5-4.0°C ‘Super El Nino’.

Temperatures in the east Pacific are now widely 5°C above average, peaking at 6°C. pic.twitter.com/voKRoioBXT

— Met4Cast - UK Weather (@Met4CastUK) August 12, 2026

Temperatures could also vary, occasionally spiking “unusually high” for a few days at a time, Brandolino said.

Parts of the country could also reach 30C earlier in the spring, and some places could reach high temperatures not felt in “several years”, he said.

A “Super El Nino”, which this is likely to be, lasts longer and increases the odds for outcomes such as high temperatures, floods, heat, humidity and fires.

El Nino typically comes around every 10-15 years, while New Zealand has had five Super El Ninos since the early 1970s.

Agriculture impact
The Ministry for Primary Industries (MPI) is encouraging farmers and growers to have a plan, national response manager Andrew Curtis said.

“It’s important farmers make decisions early, including identifying feed deficits and assessing the potential for summer feed crops.

“It could also mean prioritising livestock for destocking early and feeding the remainder as well as possible.”

El Nino can bring increased risk of drought and water scarcity, wildfires, heat-related human and animal health concerns, as well as flooding, he said.

The ministry is working with sector groups to support farmers and growers to prepare, Curtis said.

Resources through levy organisations, talking to experts who have been through El Nino before, and information on the MPI website are tools farms and growers can use, he said.