Above-average temperatures that have worsened fire-making conditions in bone-dry Nelson look set to stay for the next three months, meteorologists say.
Niwa's just-released outlook for the March to May period forecast temperatures on the warmer side for the entire country, as well as a bit of rainfall.
The North Island would receive either near or below-normal rainfall, while the west of the South Island would see above-normal totals.
Totals in the east and north of the South Island would most likely be near normal.
Niwa's Ben Noll said that the Nelson region – much of which has been sweltering in a drought – would be difficult to forecast.
Much of the North Island and upper South Island were still experiencing dry conditions, but nowhere were these more severe than the Nelson-Tasman region.
As at this week, when another fire broke out near Nelson, the region was on track for its third warmest, and third driest, summer in recorded history.
Its dry season notably featured a 40-day dry spell that ran from January 16 until Sunday, and there had only been a single day since the start of the year when rainfall levels ever climbed above 5mm.
The most dramatic figure was likely the meagre 2.4mm that Richmond received for the entire month so far – well below the 63.5mm that fell on average, and in contrast to the 211mm recorded there in the same month last year.
Noll put the region's big dry down to persistent high pressure systems in the region and a lack of northerly flows.
"We haven't had a lot of northwesterlies bringing big systems. While we've had some action in the tropics, a lot of that has stayed away from New Zealand to date," he said.
"If you compare that to last year, the region was getting hammered with ex-tropical cyclones, so there has been a massive difference."
In the short term, there was little forecast to dampen the region.
"Basically in the next five days, there's virtually nothing of note for Nelson in terms of rain – it looks very dry," MetService meteorologist Georgina Griffiths said.
"In the longer term, it looks like if we look at the broad range heading into March that drier expectation continues. New Zealand is suffering from high pressure in that region.
"The coming fortnight looks to be relatively dry for Nelson and doesn't look likely to yield decent rainfall."
Noll said March looked to be a drier month for large parts of the country as well.
"As we go through the month, there is an indication that the mid to late stages of the month may turn a little bit more active to the west and north of the country – and there may be opportunity for some rainfall.
"So we might get some unsettled conditions at the end of the month, but this doesn't look to be earth-shattering, put it that way.
"And while, certainly places in the northeast of the South Island have stood out among the rest of the regions of New Zealand as being the driest, there are places in the North Island that are also in meteorological drought, and this may expand to other areas over coming weeks."
In the North Island, areas including Taranaki and the Far North were currently rating on the drought index as "extremely dry", while a larger area, covering the lower North Island, Manawatū-Whanganui, King Country, Waikato, the Bay of Plenty, Coromandel, Auckland and Northland was classified as "very dry".
While an El Nino climate system could contribute extra warmth, moisture and an increased risk of big rainfall events over autumn, long dry spells were still the theme of its opening weeks.
Elsewhere in Niwa's outlook, sea surface temperatures in the Tasman Sea would likely remain warmer than average, and New Zealand's exposure to ex-tropical cyclones would continue to be near normal.
At least one ex-tropical cyclone passed within 550km of New Zealand each year.
Niwa is due to release its statement for the whole of summer 2018-19, expected to again be among the warmest on record, in coming days.